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Full text of "Guidebook to Constructing Inexpensive Science Teaching Equipment, Chemistry"

GUIDEBOOK TO CONSTRUCTING 



INEXPENSIVE SCIENCE TEACHING EQUIPMENT 



Volume II: Chemistry 



Inexpensive Science Teaching Equipment Project 

Science Teaching Center 

University of Maryland, College Park 
U.S.A. 



fc) Copyright. The contents of this Guidebook are open to the public domain except 
for those items which have been taken directly (as opposed to adapted) from other 
sources, and which are identified within the text by the symbol (Q . Permission to 
reproduce copyright items should be obtained directly from the relevant authors. 

June, 1972 



Inexpensive Science Teaching Equipment Project 

Science Teaching Center 

University of Maryland 



Project Director and Administrator 
J. David Lockard 

Survey Team 

Mary Harbeck 
Maria Penny 



1968-72 

1968-70 
1968-70 



Guidebook Director 

Reginald F. Melton 1970-72 

Writing, Drawing and Equipment Development Team 

Reginald Melton 1970-72 

John Delaini 1970-72 

Donald Urbancic 1970-71 

Ruth Ann Butler 1971-72 

Technical Assistants 

David Clark 1970-72 

Chada Samba Siva Rao 1970-71 



>**:. 



t* 



CONTENTS 

The Guidebook is presented in three volumes: 

Volume I, Biology 
Volume IJChemistry 
Volume II,TPhysics 

The following table refers only to the contents of this 
volume, but the listing at the back of each volume provides an 
alphabetical index to all three volumes. 

References within the text normally indicate the volume, 
chapter and number of the item referred to (e.g., BI0L/V/A3), 
but where a reference is to an item within the same volume 
the reference indicates only the chapter and number of the 
item (e.g. , V/A3) . 



-11 ■ 



n 



ii 



c. 

D. 



Table of Contents 

Foreword 

Raw Materials and Tools Required 
I. GLASSWARE TECHNIQUES AND ACCESSORIES 

A. BURNERS, TOOLS, AND EQUIPMENT 

B. GLASS 
SAFETY 
PROCEDURES FOR GLASS TUBING AND RODS 

Dl . Cutting 

D2 . Bending 

D3. Stretching 

D4. Fire Polishing Tubing 

D5. Closing Tubing 

D6. Glass Blowing 

D7. Making Rim in Tubing 

D8. Finishing Ends of Rods 

E. GLASS SHEET OPERATIONS 
El. Cutting 
E2. Drilling a Hole 

F. BOTTLE AND JAR TECHNIQUES 
Fl. Etching 
F2 . Cutting 

G. STOPPERS 
Gl. Cork Boring 
G2 . Cork Drilling 
G3 . Inserting Glass Tubing Through a Stopper 

BURNERS 



SOLID FUEL BURNERS 

Al. Candle Burner 

A2 . Charcoal Burner 

LIQUID FUEL BURNERS 

Bl. Simple Alcohol Burner 

B2 . Modified Alcohol Burner 
GAS BURNERS AND SYSTEMS 

CI. Fuel System for Gas Burner 

c2. Gas Burner 

C3. Wing Tip 



Page 

vii 

x 

: 
2 

4 
6 

a 
9 
12 

13 
14 
15 
16 
17 

19 
20 

22 
24 
29 
30 
32 
33 
34 

35 
36 

3a 

40 

43 
49 
54 



•Ill- 



III. 



MEASURING APPARATUS 



i- 

U 



A. DEMONSTRATION DEVICES 

Al . Demonstration Thermometer 
A2 . Bi-Metal Strip 

B. VOLUMETRIC MEASURES 
Bl. Burette 

B2. Measuring Glass 
B3. Dropper 
B4. Pipette 
B5. Volumetric Flasks 
B6. Specific Gravity Bottle 
IV. SUPPORTS; STANDS, AND HOLDERS 

A. HOLDERS 

Al. Tweezers (Forceps) 

A2 . Multi-purpose Design Holder 

A3. Test Tube Holder 

A4 . Wooden Pinch Clamp 

A5 . Wooden Screw Clamp 

B. SUPPORTS AND STANDS 
Bl. Wire Gauze 

B2. Heating Shelf 
B3 (1) . Tripod (Tin Can) 
B3(2). Tripod (Strapping) 
B3 (3) . Tripod (Wire) 



B4 
B5 
B6 

B7 



B' 
BIO. 



Collapsible Heating Stand 
Ring and Burette Stand with Attachments 
Multipurpose Stand 
Rack for Light Bulb Glassware 
Stand for Light Bulb Glassware 
Bamboo Test Tube Rack 
Wooden Test Tube Rack 



GLASSWARE AND CROCKERY 
A. GLASSWARE 

Al . Light Bulb Glassware 

A2 . Beaker 

A3. Funnel 

A4. Bell Jar 

A5 . Watch Glass 

A6. Petri Dish 

A7. Wash Bottle 



57 
59 

61 
64 
66 
67 
68 
69 



72 
73 
76 
78 
80 

82 
83 

84 

86 

87 

88 

90 

98 

100 

102 

103 

105 

106 

107 
109 
110 
111 
112 
113 
114 



A8 . Aspirator 117 
B. CROCKERY 

Bl. Mortar and Pestle 120 

VI, SEPARATORS AND PURIFIERS 124 

A. MECHANICAL SEPARATORS 

Al. Magnets 125 

A2 . Cone Sieve 126 

A3. Basket Sieve 127 

A4. Suction-Filter Flask 129 

A5 . Separatory Funnel 132 

B. DISTILLATIONAPPARATUS 

Bl. Simple Distillation Apparatus 136 

B2 . Condenser 138 

B3. Water Still 141 

C. ELECTRIC-SEPARATOR 

CI. Electrolysis Apparatus 145 

D. CENTRIFUGAL SEPARATORS 

Dl. Hand Drill Centrifuge 149 

D2 . Centrifuge 153 

VII. GAS GENERATORS 162 

A. GAS GENERATORS 

Al. Simple Gas Generator and 

Collecting Apparatus 163 

A2. Flask Generator 165 

A3. Kipp's Generator 167 

B. ACCESSORIES 

Bl. Beehive Shelf 173 

B2 . Metal Sheet Shelf 174 

VIII. METALWARE AND CLEANER 175 



A. METALWARE 

Al. Flame Test Wire 176 

A2. Deflagrating "Spoon" 177 

A3. Spatula 178 

B. CLEANER 

Bl. Test Tube Cleaner or Spatula 179 



IX. HEATERS AND DRYERS 180 



A. DRYERS 

Al. Dessicator 181 

A2. Drying Tower 183 

A3. Electric Lamp Dryer 185 

A4. Sand Bath 188 

A5. Water or Steam Bath 189 

B. HEATER 

Bl. Blowpipe for Charcoal Block 191 

X. MOLECULAR MODELS 192 

A. SPACE-FILLING MODELS 

Al. Ball-and-StickModels 193 

B. SKELETAL MODELS 

Bl. Molecular Model Units 198 

B2. Single Bond Structures 203 

B3. Double Bond Structures 207 

B4 . Triple Bond Structures 213 

B5. Geometric Structures 215 

C. CRYSTAL STRUCTURE MODELS 

CI. Crystalline Packing Models 217 

D. KINETIC-MOLECULAR MODEL 

Dl . Kinetic Theory Model 220 

XI. CHROMATOGRAPHIC APPARATUS 223 

A. QUALITATIVE CHROMATOGRAPHIC APPARATUS 

Al. Horizontal Paper Chromatography Device 224 

A2 . Horizontal Paper Chromatography Device 226 

A3. Horizontal Paper Chromatography Device 228 

A4. Vertical Paper Chromatography 

Eguipment 230 

A5 . Vertical Strip Paper Chromatography 

Equipment 234 

B. QUANTITATIVE CHROMATOGRAPHIC EQUIPMENT 

Bl. Liquid-Column Apparatus 237 



XII. MULTIPURPOSE SYRINGES 



241 



A. TECHNICAL DEVICES 
Al. Dropper/Pipette 
A2 . Pump 

B. GAS STUDIES APPARATUS 

Bl. Gas Production and Collection Device 
Micro-Generator 



B2. 
B3. 



Gas Solubility Device/Reaction 
Rate Chamber 

Charles' Law: Volume/Temperature 
Device 



C 



DI FFUSION APPARATUS 

CI. Liquid Diffusion Device 

C2 . Gas Diffusion Device 

D. OXIDATION APPARATUS 

Dl. Oxidation Indicator: Membrane Type 
D2. Oxidation Indicator: Displacement Type 
D3. Oxidation Rate Indicator 
D4. Stoichiometry Device 

E. ANALYTICAL APPARATUS 

El. Air Composition Device 
E2. Gas Reaction Chamber 
F . CONDUCTANCE APPARATUS 

Fl . Conductance Device 

F2 . Constant Volume Conductance Device 

Bibliography 

Alphabetical Index 



242 
243 

245 
249 

250 

252 

254 
255 

258 
260 
262 
263 

266 
268 

270 
273 

276 
278 



FOREWORD 



History 

The Inexpensive Science Teaching Equipment Project was initiated by Dr. J. David 
Lockard, and got underway under his direction in the summer of 1968. Originally entitled 
the Study of Inexpensive Science Teaching Equipment Worldwide (IS-TEW or IS-2 Study), 
the Project was to (1) identify laboratory equipment considered essential for student 
investigations in introductory biology, chemistry and physics courses in developing 
countries; (2) improvise, wherever possible, equivalent inexpensive science teaching 
equipment; and (3) produce designs of this equipment in a Guidebook for use in develop- 
ing countries . Financial support was provided by the U.S. Agency for International 
Development through the National Science Foundation. 

The initial work of the Project was undertaken by Maria Penny and Mary Harbeck 
under the guidance of Dr. Lockard. Their major concern was the identification of 
equipment considered basic to the teaching of the sciences at an introductory level. 
An international survey was conducted, and a list of equipment to be made was compiled. 
A start was also made on the writing of guidelines (theoretical designs) for the 
construction of equipment. 

Work on the development of the Guidebook itself got underway in 1970, with the 
arrival of Reginald F. Melton to coordinate the work. Over 200 guidelines were completed 
during the year by Donald Urbancic (Biology) , Chada Samba Siva Rao and John Delaini 
(Chemistry), and Reginald Melton (Physics). Full use was made of project materials from 
around the world which were available in the files of the International Clearinghouse on 
Science and Mathematics Curricular Developments, which is located in the Science 
Teaching Center of the University of Maryland. The guidelines were compiled into a 
draft edition of the Guidebook which was circulated in September, 1971, to some 80 
science educators around the world for their comments and advice. 

The work of constructing and developing equipment from the guidelines, with the 
subsequent production of detailed designs, began in a limited way in 1970, the major 
input at that time being in the field of chemistry by Chada Samba Siva Rao, who was 
with the project for an intensive two-month period. However, the main work of developing 
detailed designs from the guidelines was undertaken between 1971 and 1972 by John Delaini 
(Biology), Ruth Ann Butler (Chemistry) and Reginald Melton (Physics) . Technical 
assistance was given by student helpers, with a special contribution from David Clark, 
who was with the project for a period of 18 months. 



LA 



Thanks are due to those graduates, particularly SamuelGenova, Melvin Soboleski 
and Irven Spear, who undertook the development of specific items of equipment while 
studying at the Center on an Academic Year Institute program; to student helpers, 
especially Don Kallgren, Frank Cathell and Theodore Mannekin, who constructed the 
equipment; and to Dolores Aluise and Gail Kuehnle who typed the manuscripts. 

Last, but not least, special acknowledgement is due to those individuals, and 
organizations, around the world who responded so willingly to the questionnaires in 
1968 and to the draft edition of the Guidebook in 1971. 

The Guidebook 



The designs presented in the Guidebook are based on the premise that many students 

T"~! and teachers in developing countries will wish to make equipment for themselves. This 

I j does not mean that students and teachers are expected to produce all their own apparatus i 

requirements. It is recognized that teachers have specific curricula to follow, and that 1 

..] j "class hours" available for such work are very limited. It is also recognized that ; 

teachers, particularly those in developing countries are not well paid, and often i 

i 
augment their salaries with supporting jobs, thus placing severe limits on the "out-of- I 

class hours" that are available for apparatus production. j 

However, in designing equipment for production by students and teachers, two factors i 
have been kept in mind. One, project work in apparatus development can be extremely 
rewarding for students, bringing both students and teachers into close contact with the ■ 
realities of science, and relating science and technology in the simplest of ways. Two, 
it is not difficult for cottage (or small scale) industries to adapt these designs to 
their own requirements. The Guidebook should therefore not only be of value to students 
and teachers, but also to cottage industries which may well be the major producers of 
equipment for schools. 

Although all the designs in the Guidebook have been tested under laboratory 
conditions in the University of Maryland, they have not been tested in school situ- 
ations nor produced and tested under local conditions in developing countries. It is 
therefore recommended that the designs should be treated primarily as limited resource 
materials to be subjected to trial and feedback. It is suggested that the first time 
that an item is constructed it should be made precisely as described in the Guidebook, 
since variations in the materials, or the dimensions of the materials, could alter the 
characteristics of the apparatus. However, once this item has been tested the producer 
is encouraged to make any number of modifications in the design, evaluating the new 
products against the original. 



Before producing new equipment in quantity, it is recommended that educators 
with experience in the field of science education should be involved in determining 
how best to make use of the Guidebook. They will wish to relate the apparatus to their 
own curriculum requirements, and, where necessary, prepare relevant descriptions of 
experiments which they recommend should be undertaken using the selected apparatus. 
They will want to subject the experiments and related equipment to trials in school 
situations. Only then will they consider large-scale production of apparatus from the 
designs in the Gu idebook. At this stage educators will wish to control the quality of 
apparatus production, to train teachers to make the best use of the new apparatus, and 
to insure that adequate laboratory conditions are developed to permit full utilization 
of the apparatus. Too often in the past apparatus has sat unused on many a classroom 
shelf, simply because the teacher has been untrained in its usage, or the laboratory 
facilities have been inadequate, or because the apparatus available did not appear to 
fit the requirements of the existing curriculum. Such factors are best controlled by 
educators in the field of science education in each country. Clearly the science 
educator has a crucial role to play. 

Apparatus development, like any aspect of curriculum development, should be 
considered as a never ending process. This Guidebook is not presented as a finished 
product, but as a part of this continuing process. There is no doubt that the designs 
in this book could usefully be extended, descriptions of experiments utilizing the 
apparatus could be added, and the designs themselves could be improved. No extravagant 
claims are made concerning the Guidebook. It is simply hoped that it will contribute 
to the continuing process of development. 



-x- 



TOOLS AND RAW MATERIALS 



The raw materials required to make specific items of equipment are indicated at 
the beqinninq of each item description. However, there are certain tools and materials 
which are useful in any equipment construction workshop, and these are listed below. 

Tools 



Chisels, Wood 

3, 6, 12, 24 mm 

(i.e., 1/8", 1/4", 1/2", 1") 

Cutters 

Bench Shears: 3 mm (1/8") capacity 

Glass Cutter 

Knife 

Razor Blades 

Scissors: 200 mm(8") 

Snips (Tinmans), Straiqht: 200 mm (8") 

Snips (Tinmans), Curved: 200 mm (8") 

Taps and Dies: 3 to 12 mm (1/8" to 1/2") set 

Drills and Borers 

Cork Borer Set 

Countersink, 90' 

Metal Drill Holder (Electrically Driven) , Capacity 6 mm (1/4") 

Metal Drills: 0.5, 1, 2, 3, 4, 5, 6, 7 mm 

(i 1/32" 1/16" 3/32" 1/8" 5/32", 3/16", 7/32", 1/4") set 
Wood Brace with'Ratchei : 250'mm (10") 
Wood Auqur, Bits: 6, 12, 18, 24 mm 

(i.e., 1/4", 1/2", 3/4", 1") 

Files, Double Cut 

Flat: 100 mm, 200 mm (4", 8") 
Round: 100 mm, 200 mm (4", 8") 
Triangular: 100 mm (4") 

Hammers 

Ball Pern: 125, 250, (1/4, 1/2 lb) 
Claw 250 g (1/2 lb) 

Measuring Aids 

Caliper, Inside 

Caliper, Outside 

Caliper, . Vernier (may replace above two items) 

Dividers: 150 mm (6"), Toolmakers 

Meter, Electrical (Multipurpose- volts, ohms, amps, etc.) 

Meter Stick 

Protractor 

Scriber 



Measuring Aids (Continued) 

Set Square 

Square, Carpenter's: 300 mm (12") blade 

Spoke Shave: 18 mm (3/4") 

Wood Smoothing Plane 

Pliers 

Combination: 150 mm (6") 
Needle Nose: 150 mm (6") 
Side Cutting: 150 mm (6") 
Vise Grips 

Saws, Metal 

300 mm (12") blades 

Saws, Wood 

Back Saw: 200, 300 mm (8", 12") 
Coping Saw: 200 mm (8") 
Cross Cut: 600 mm (24") 
Hand Rip: 600 mm (24") 
Key Hole Saw: 200 mm ( 8 " ) 

Screw Drivers 

100 mm (4") with 2 and 3 mm tips 
150 mm (6") with 5 mm tip 
200 mm (8") with 7 mm tip 

Vises 

Metal Bench Vise: 75 I1U1 (3") 
Wood Bench Vise: 150 mm (6") 

Miscellaneous 

Asbestos Pads 

Goggles, Glass 

Oil Can: 1/2 liter pint) 

Oil Stone, Double Faced 

Punch, Center 

Sandpaper and Carborundum Paper, Assorted grades 

Soldering Iron: 60 watts, 100 watts 



Raw Materials 



Adhesives 

All Purpose Cement (Elmers, Duco) 

Epoxy Resin S Hardener (Araldite) 

Rubber Cement (Rugy) 

Wood Glue (Weldwood) 

Cellophane Tape 

Plastic Tape 

Masking Tape 



Electrical Materials 

Bulbs with Holders: 1.2, 2.5, 6.2 volts 
Dry Cells: 1.5, 6 volts 

Electrical Wire: Cotton or Plastic covered 
Fuse Wire: Assorted 
Lamps: 50, 75, 100 watts 
*Magnet Wire: #20, 22, 24, 26, 28, 30, 32, 34 
Nichrome Wire: Assorted 
Parallel Electrical Cording 
Plugs 
Switches 

Glass and Plastic 

Acrylic (Plastic) Sheets: 2 cm and 2.5 cm thick 

Plates, Glass 

Tubes, Glass: 3, 6 mm (1/8", 1/4") internal diameter 

Hardware 

Bolts and Nuts, Brass or Steel; 3 mm (1/8") diameter: 12, 24, 48 mm 

(1/2", 1", 2") lengths 
Nails: 12, t 7A mm (1/2", 1") lengths 
Screws, Eye 

Screws, Wood: 12, 18, 24, 26 mm (1/2", 3/4", 1", \ 1/2") lengths 
Thumbtacks 

Washers (Brass and Steel) : 6, 9 mm (1/4", 5/16") diameter 
Wingnuts (Steel) : 5 mm(3/16") 

Lumber 

Boxwood (Packing Case Material) 

Hardboard: 6 mm (1/4") thick 

Kiln Dried Wood: 2.5 x 15 cm (1" x 6") cross section 

1.2 x 15 cm (1/2" x 6") cross section 
Plywood: 6, 12 mm (1/4", 1/2") thickness 
Wood Dowels: 6, 12 mm (1/4", 1/2") thickness 



* U. S. Standard Plate numbers are used in this book to indicate the gauge of 
different wires. Where wires are referenced against other numbering systems 
appropriate corrections should be made in determining the gauges of materials required. 
The following comparison of gauges may be of interest: 

Standard Diameter of #20 Wire 



Brown & Sharp 0.08118 

Birmingham or Stubs 0.089 

Washburn & Moen 0.0884 

Imperial or British Standard 0.0914 

Stubs' Steel 0.409 

U. S. Standard Plate 0.09525 



Metal Sheets 

Aluminum: 0.2, 0.4 mm (1/100", 1/64" ) thickness . 
Brass: 0.4, 0.8 mm (1/64", 1/32") thickness . 
Galvanized Iron: 0.4 mm (1/64") thickness. 
Lead: 0.1mm (1/250") thickness . 
Spring Steel, Packing Case Bands 

Metal Tubes: 

Aluminum, Brass, Copper: 6, 12 mm (1/4", 1/2") internal diameter . 

Metal Wires 

Aluminum: 3 mm (1/8") diameter 

Coathanger: 2 mm (1/16") diameter 
*Copper: #20 24 

Galvanized Iron: 2 mm (1/16") diameter 
*Steel: #20 26, 30. 

Paint Materials 

Paint Brushes 
Paint Thinner 
Varnish 
Wood Filler 

Miscellaneous 

Aluminum Foil 

Cardboard Sheeting 

Containers (Plastic or Glass) 

Corks (Rubber or Cork) 

Grease 

Hinges: Assorted 

Machine Oil 

Marbles 

Mesh (Cotton, Nylon, Wire) 

Modelling Clay (Plasticene) 

Paper Clips 

Pens: Felt (Marking Pens) 

Pins and Needles 

Rubber Bands 

Soldering Lead 

Soldering Paste 

Spools 

Steel Wool 

Straws 

String (Cord, Cotton, Nylon) 

Styrofoam 

Syringes: Assorted 

Wax (Paraffin) 



*See footnote on previous page. 



I. GLASSWARE TECHNIQUES AND ACCESSORIES 

Equipment made of glass or using glass components has applications in all branches 
of science. This chapter includes some basic glass-working techniques that will be 
necessary for constructing much of the equipment in this book. 

These are presented in sections which describe the type of equipment needed, the 
type of glass to use j and techniques for working with several forms of glass. 



.J 



A. BURNERS, TOOLS, AND EQUIPMENT 

This section discusses burners that can be used in working glass, as well as 
listing the tools and other items necessary for working with glass. 

B. GLASS 



This section describes the type of glass that works best with the burners listed 
in section A. 

C. SAFETY 



Notes for safe handling and working of glass are given here. 
P. 'PROCEDURES FOR GLASS TUBING AND RODS 

Directions for working with glass tubing and solid rods are given in this section. 

E. GLASS SHEET OPERATIONS 

This section tells how to cut and drill glass sheets. 

F. BOTTLE AND JAR TECHNIQUES 

Much useful laboratory glassware can be made by using discarded bottles and jars. 
This section includes directions for cutting and drilling these items. 

G. STOPPERS 



This section discusses types of stoppers and describes techniques for drilling 
holes in them. 



A. BURNERS, TOOLS, AND EQUIPMENT 

Glass-working techniques described here are designated for use with Modified 
Alcohol Burner (II/B2), and the Gas Burner (II/C2) . Of these, the gas burner, if 
available, is most highly recommended. 

The general items required for general glass-working techni'ques are as follows: 

Glass Cutter 




^ 



o 



Triangular File 




Round File 



Set of Cork-borers 





Pliers 

Brick or Asbestos Pads 

Rags or Pieces of Cloth 

Clean rags, or pieces of cloth no smaller than about 10 cm x 10 cm. 



String 

Kerosene 

Camphor 

Ruler 

Blotting Paper or Paper Towels 

Emery Paper 

Container of Sand 



GLASS 



There are many different types of glass, with different properties, depending upon 
the chemical composition of the glass. Two very common types of glass that are dis- 
cussed here are "soft glass" and "hard glass." 

Soft Glass 



This term includes a number of the oldest known and most common types of glass in 
general use. Most bottles, jars, window glass, and much glass tubing and rods are 
made of some type of soft glass. Such glass is used for items of simple design and 
moderate thickness, that will not be subjected to very high temperatures. 

One of the most important properties of soft glass, from the point of view of this 
book, is that it can be softened in the heat of an air-gas flame. This is the type of 
flame produced by the burners specified in section A. Also, soft glass has a wide 
range of working temperatures, which makes it easy to work even after it has been 
removed from flame. 

Although it is easy to work, soft glass has some limitations and must be used with 
care. An empty container of soft glass cannot be greatly heated, or it will crack. 
I£however, such a container holds a liquid or powder, it can safely be heated, 
slowly. Also, a soft glass container, with or without anything inside, must not be 
suddenly cooled when hot or suddenly heated when it is cold. Otherwise, it will break. 

Hard Glass 



Hard glass has been developed during the twentieth century. Of a number of types 
produced, "Pyrex" is one of the most common brand names., Most manufactured laboratory 
glassware is now made of hard glass, which is harder stronger, more chemically inert, 
and safer to use over a wider temperature range than soft glass. 

Laboratory glassware made of hard glass is safer than soft glass. It can be 
rapidly heated or cooled to greater temperature extremes without danger of breaking. 
It does not scratch easily, and it does not break as easily as soft glass if struck or 
dropped. 

Although it is often manufactured into laboratory glassware, hard glass is not 
generally made into the bottles and jars that are used for much of the apparatus 
described in this book. Therefore, it is not as generally available as soft glass. 
As tubing, rods, and sheets, it is usually more expensive than the same items made of 
soft glass. 

Hard glass's most important disadvantage here is that it must be worked in an 
oxygen-enriched flame. The burners described in section A cannot heat hard glass hot 
enough for working. 

Therefore, only soft glass is suitable for use with the alcohol or gas burners 



described. The techniques here listed have been tested using soft glass and the air- 
gas flames produced by such burners. 

Testing for Soft Glass 

To determine whether a piece of glass is "hard glass" or "soft glass", heat it in 
the flame of an alcohol or gas burner. Ifthe glass begins to glow and soften enough 
to be easily worked, it is soft glass. If it does not soften, it is hard glass and 
cannot be worked without specialized equipment. 



■._i 



C. SAFETY 

Glass working, like most other laboratory procedures, carries a set of risks. By 
arranging a safe work area and taking a few precautions, however, most such risks can 
be avoided. 

Sharp Edges and Points 

There is always a danger of being cut by sharp points and edges of broken or cut 
glass. Be careful of such edges and points, and try to handle the glass away from the 
edges. Fire polish or smooth with emery paper any cut edges or points that are part 
of a finished project. Keep such edges away from the mouth and eyes at all times, and 
keep the work area clear of waste glass. 

Burns 



Hot glass looks just like cool glass! To avoid burns, allow heated glass to cool 
before handling it. Rest it on bricks or asbestos pads, or in a container of sand. 
Before picking up a piece of previously heated glass, touch it lightly with the finger- 
tips to check that it is cool enough to handle. In cases where hot or warm glass must 
be handled, protect the hands with a holder of several layers of cloth, or use holders 
such as those described in the section on holders (IV) . Protect the body from burns 
with clothing, an apron, overall, or laboratory coat. 

Fire 

Both the burner flame and hot glass can start a fire. Prevent this by keeping all 
flamable material, such as paper or cloth away from the flame and any hot glass. Set 
hot glass down on things that will not burn, such as bricks, asbestos pads, or sand. 
To keep hair or clothing from being singed or igniting, tie back long hair, roll up 
sleeves, and secure loose clothing close to the body. Inspect the burner, fittings, 
tubing, and fuel supply each time the equipment is used to prevent leaks of fuel that 
might lead to a fire. If any alcohol should spill, immediately put out the flame and 
mop up the spill . 

The container of sand mentioned for holding hot glass is also useful for fire con- 
trol. If paper, cloth, or spilled alcohol should ignite, smother the fire by dumping 
sand on it. If on the other hand, the gas burner system (II/Q]is used and a fire 
develops, get away fast! 

Eye Damage 

To prevent eye damage, keep all sharp edges and points, all hot glass, and all 
flames away from the eyes. Wear safety goggles or eye glasses to provide additional 
protection for the eyes. 



Gas Danger 

If natural gas or bottled gas is used as fuel for the burner, a leak in the system 
can release gas that is poisonous to breathe. To avoid this danger, inspect all pipes, 
tubing, and fittings often. 



L_ 



n 



D. PROCEDURES FOR GLASS TUBING AND RODS 



Dl. Cutting 

a. Materials Required 

Length of soft glass tubing or solid rod 

Triangular file 
Ruler 

b. Procedure 



£ 




Lay the tubing or rod flat on 
the work surface and measure 
the desired length. Make a 
scratch on the glass at this 
point by drawing one edge of 
the file across the tube. Press 
hard enough with the file to 
make a deep scratch. 



scratch 




Moisten the scratch, then grasp 
the glass firmly in both hands 
with the thumbs on the side of 
the tube opposite the scratch. 
Apply pressure with the thumbs 
while pulling out and down with 
the hands until the tube or rod 
snaps cleanly. 



D2. Bending 

a. Materials Required 

Burner: wide-flame alcohol burner 
or 
wing tip with gas burner 

Length of soft glass tubing or solid rod 

Cooling surface: brick 
or 
asbestos pad 

b . Procedure 



Gravity Bending 



S> 



_i 





With one hand, hold the tubing 
or rod, just above the inner 
cone of the flame. Rotate the 
tubing to heat it evenly until 
the free end droops under its 
own weight. 



■SZ: 



* 



Remove the glass from the 
flame. It should bend to a 
right angle. Allow it to cool. 



Manual Bending 




Install the wing tip on the gas 
burner, and light the burner. 
Hold each end of the tubing or 
rod. Support the glass so that 
it is level, with its middle in 
the hottest part of the flame. 
Turn the tubing or rod back and 
forth by rotating the thumb and 
first finger. Continue to heat 
it evenly until it softens. 



-10- 




Bend Up 



Bend Up 



When the tubing or rod is soft, 
remove it from the flame. Imme- 
diately, bend the ends up until 
the tubing or rod is bent at a 
right angle (90 ' ) . 

Rest the hot tubing or rod on a 
brick or other cooling surface. 



C. Notes 

(i) If a wing tip is not available or if a standard alcohol burner is used, 
the tubing or rod must be heated differently. Hold each end of the glass and 
support it so that it is level with the middle just above the inner core of 

flame. Rotate the tubing back 

4 ■ c 




A 




v> A. 



u^ 



and forth. At the same time, 
move it to the left and right 
so that about 0.3 cm of its 
length of evenly heated. Con- 
tinue to both rotate and move 
the tubing or rod until the 
heated section softens. 
Remove from the flame and bend 



it as described above. 



(ii) With a little practice with glass tubing, you should be able to achieve a 

bend in which the opening stays 



Properly 
Heated 



Q_ 



i\ 



Under Heated 



the same throughout the bend. 

Overheating or underheating the 
tubing, however, will produce 
poor bends. Underheating causes 
the tube to fold in at the bend. 
Overheating causes the tube to 
collapse at the bend. 



d 



over Heated 



<~j 



-11- 



(iii) If a U-shaped bend is desired, first make one 90° bend as described above. 

After allowing the glass to 
cool, make another 90' bend 
near the first one. 



fl 



J 



-12- 



D3 . Stretching 

a. Materials Required 

Burner: wide-flame alcohol burner 
or 
wing tip with gas burner 

Length of soft glass tubing or rod 

b. Procedure Hold the glass tubing or rod in 

the flame. Turn it as it heats, 

just as for making a bend. 

< } 

■*--~" ** ' Heat the glass evenly until it 



<L 



Pull Apart t" softens. When the tubing or 

rod is soft, remove it from the 
flame. Pull the ends apart 
until the center has become 
narrow and stretched about 
25 - 30 cm. 



> < 



After the stretched part has 
cooled, it can be cut as 
required (I/Dl) . Carefully 
fire polish the edges (I/D4) . 



c. Notes 



(i) Stretched glass tubing has many applications in laboratory glassware. For 
example, the ends of the stretched tubing pictured above, with a narrow opening at 

j. ^ one end, may be used as nozzles 

or jets. 
The very narrow section of the tubing, the stretched part, may be used as a capil- 
fl =3 lary tube. 

(ii) If a wing tip or wide-flame burner is not available, follow the procedure 
given for heating a wide area of glass without the wing tip [I/D2, Note (i)] . 



•13- 



D4. Fire Polishing Tubing 

a. Materials Reguired 

Glass tubing with cut edge 

Burner 

Cooling surface 

b. Procedure 




Rough Edge 
of Tubing 



c. Notes 



Hold the rough, cut end of the 
glass tubing in the hottest 
part of the flame, just above 
the inner cone. Turn the 
tubing constantly until the 
edge glows red. 

Remove the tubing from the 
flame. Examine the heated end. 
If it is now rounded smoothly, 
rest the hot tubing on a brick, 
asbestos pad, or sand to cool. 
If the other end of the tubing 
is also rough, repeat the fire 
polishing procedure . 



(i) Do not overheat the end of the tubing, or it will tend to close entirely. 

(ii) Fire polish the ends of all glass tubing in use, as a safety measure. 

(iii) Tubing with thick walls — for example, 0.5 cm (inside diameter) and larger — 
must be annealed to prevent cracking. To do this, hold the end in the flame for 
about one second, then remove from the flame for about one second. Repeat this 
procedure eight or ten times, then hold the end in the flame, turning it con- 
stantly until it is red hot. To cool thick-walled tubing slowly, remove it from 
the flame, but hold the tubing near the flame for a few seconds. Gradually move 
the hot end of the tubing further from the flame until it can be rested on the 
brick or other cooling surface. 



-14- 



D5, Closing Tubinq_ 

a. Materials Required 
Burner 

Glass tubing 

Cooling surface 

b. Procedure 

Narrow Tubing 



Wide Tubing 



-« ^ 



CE 




D 



When using tubing with a 
diameter of less than 1.0 cm, 
hold the end of the tubing in 
the hottest part of the flame, 
just as for fire polishing. 
Turn the tubing constantly. 
Continue heating until the end 
closes . 

When using tubing with a dia- 
meter greater than 1.0 cm, 
heat the tubing near one end, 
rotating the tubing as it heats. 
When the tubing is soft, pull 
it apart. 

Continue to heat and pull the 

ends apart until the ends 

separate and the pointed end 
has closed. 



-15- 



._J 



D6, Glass Blowing 

a. Materials Required 
Gas burner 

Length of soft glass tubing 

Cooling surface 

b. Procedure 




3) 



o 



c .Notes 



Fire polish one end of the 
tubing. Allow it to cool. 
Close the_ other end by heating 
in the flame. Heat the closed 
end, rotating it constantly. 
While continuing to heat and 
rotate the tube, blow very 
gently, in short, light puffs, 
into the open end of the tube. 
Just as the closed end of the 
tube begins to swell and glow 
pale red, remove it from the 
flame. Blow strongly into the 
tube, while rotating it, to 
form a small round bulb. 



(i) This procedure takes practice and patience to learn. It is helpful to 
begin with the narrowest tubing available; 0.3 cm tubing, for example. A common 
problem is blowing out the side of the bulb while the tubing is still in the flame. 

(ii) A limiting factor in the size of tubing that can be used and the size of 
the bulb that can be blown is the burner used. The gas generating system 
(Il/tjimd burner (II/C2) are adequate to allow 0.3 cm and 0.5 cm tubing to be 
blown into bulbs about 0.8 cm in diameter. 



-16- 



D7 . Making Rim in Tubing 

a. Materials Reguired 
Burner 

Glass tubing 

Triangular file 

Brick, or asbestos pad 

b. Procedure 



Flattening 



Push Down 




Hold one end of the tubing in 
the hottest part of the flame. 
Turn it constantly until the 
edge glows red. Remove the 
tubing from the flame. Quickly 
push the hot end evenly down 
against the brick or asbestos 
pad. A lip should form. 
Allow the glass to cool. 



Flaring 




Heat one end of the tubing 
until it is red hot. Remove 
the tubing from the flame. 
Hold the thin handle end of the 
file inside the end. Press 
gently outward on the file, 
while turning the tube to form 
a flared edge. 
Allow the glass to cool. 



-17- 



,- 1 



D8. Finishing Ends of Rods 

a. Materials Required 
Soft glass rods 

Burner 

Brick, or asbestos pad 

Pliers 

b. Procedure 

Fire Polishinq_ 



o 



Flattening, 




Squeezing 




Follow the procedure for fire 
polishing glass tubing (I/D4) . 
It will be necessary to heat 
the end of the rod for a longer 
period of time. The fire 
polished end will have a small, 
solid bulb. Holding the rod 
in the flame for a longer time 
will produce a larger bulb at 
the end. 
Allow the rod to cool. 

Follow the procedure for 
flattening glass tubing (I/D7) 
to form a flat disc at the end. 
Allow the rod to cool. 

Heat one end of a rod as before. 
When it is hot, remove it from 
the flame. Compress about 1 cm 
of the end of the rod between 
the jaws of the pliers. A 
flattened paddle-shaped end will 
form. 
Allow the rod to cool. 



L 




c. Notes 

(±& useful stirring rod can be made with a rod of about 0.3 - 0.5 cm diameter, 
15 - 20 cm long. Flatten one end and squeeze or fire polish the other. 



t 



-19- 



GLASS SHEET OPERATIONS 



El. Cutting 

a. Materials Required 
Glass cutter 

Sheet of glass 

(for example, a pane of window glass) 



b. Procedure 




Push Down 




Lay the glass flat on bench 
of table. Hold the ruler along 
the line to be cut, with one 
hand; and with the other hand, 
draw the wheel of the glass 
cutter on the glass along the 
ruler. Press hard enough to 
scratch the glass. 

Place the underside of the 
scratch exactly over the edge 
of the table or bench. Press 
down on both sides to break 
the glass cleanly along the 
scratch. 



•20- 



E2 . Drilling a Hole 

a. Materials Required 
Sheet of glass 

Triangular file 

Hammer 

Turpentine 

Camphor 

b. Procedure 





2ZX4- 



Broken Corners 



-Turpentine And 
camphor 



Take a little turpentine in a 
bottle cap. Put a small amount 
of camphor in it. Chip off the 
end of the triangular file with 
a hammer. This chipped end 
has sharp corners. 



Drop of 
Turpentine 
Camphor 




Place the glass flat on a 
table. Dip one of the sharp 
corners of the broken file into 
the turpentine-camphor mixture. 

Press this corner of the file 
down on the spot to be drilled. 
Twist the file back and forth 
to drill into the glass. Use 
more turpentine-camphor as 
needed and continue drilling 
until the hole is complete. 



-Zl- 



c. Note s 

(i) Drilling by hand is slow and may take ten or fifteen minutes. 

(ii) A completed hole can be enlarged with the edge of the triangular file or a 
round file, and the turpentine-camphor mixture. 

(iii) After making the beginning hole on the surface of the glass, it is in fact 
easier to use a hand drill with the triangular file as the bit. However, extreme 
care must be taken. Do not push down on the drill at all, or the glass might 
break. Let only the weight of the drill be the force on the glass. 

(iv) Follow this same procedure to drill a hole in a glass bottle or jar. 



-22- 



F. BOTTLE AND JAR TECHNIQUES 



Fl. Etching 




(1 ) Etching Guide 



a. Materials Reguired 
Components 
(1) Etching Guide 



b. Construction 

(1) Etching Guide 



(A) 



Qll I tems Required 
1 Wood (A) 

1 Wood (B) 




Dimensions 

Approximately 10 cm x 
20 cm x 1 cm 

Approximately 10 cm x 

10 cm x 1 cm 



Cut V-shaped notches into one 
edge of a wooden board (A) . 
Make the notches about 1 cm 
deep and about 2 cm (or other 
desired interval) apart. Then 
secure the base (B) at right 
angles to (A) with nails or glue 
and screws. 



c. Notes 

(i) The etching guide is used in combination with a triangular file or glass 
cutter to scratch a continuous line on a bottle or jar, prior to cutting. The 



-23- 




Cutting 
Tool 



bottle or jar is placed on the 
stand and a glass cutter or 
triangular file is placed in 
a notch at the desired height. 
The bottle is rotated, and 
pressure is maintained against 
it with the tool so that a 
continuous scratch is scored 
around it . 



(ii) A second method for etching a bottle, jar, light bulb, etc. to be cut is 
to wrap a strip of adhesive tape or paper around the glass as a guide. After the 
line has been scratched completely around the glass, the tape is removed. 

(iii) After the glass has been etched in either of these two fashions, it may be 
cut using one of the technigues described in the following section. 



-24- 



F2. Cutting 

Electrical Heating 



(3) Wi 




(2) Terminal 



(1) Stand 



a. Materials Required 
Components 

(1) Stand 

(2) Terminal 

(3) Wiring 



b. Construction 



(1) Stand 



Qu 


Items Required 


l 


Wood (A) 


2 


Wood (B) 


2 


Bolts (C) 


4 


Nuts (D) 


1 


Nichrome Wire (E) 



^L^ 



Hole . 



Insulated Copper Wire (F) 



Dimensions 

30 cm x 10 cm x 2 cm 

25 cm x 4 cm x 2 cm 

3 cm long, . 5 cm 
diameter 

. 5 cm 

Size #24 (0.06 cm 
diameter) , 34 cm long 

Size #20 (0.08 cm 
diameter) , 125 cm long 




Drill a hole in one end of each 
of the two uprights (B) . This 
hole should be slightly smaller 
in diameter than the bolts (C) 
used for the terminals. Next, 
nail or screw the uprights to 
the base (A) . 



-25- 



(2) Terminal 




Cut the heads off the two bolts 
(C) , and put glue into the holes 
in the uprights (B) . Screw the 
bolts down into the hole, 
leaving about 1.5 2 cm pro- 
truding. Next, secure the 
bolts by screwing on one nut (D) 
until it is tight. Screw on 
the second nut (D) loosely. 



(3) Wiring 




C. Notes 



wrap one end of the #24 ni ch- 
rome wire (E) around one bolt 

(C) for one or two turns and do 
the same with the other end. 
Tighten the second nut (D) on 
the terminals until the nich- 
rome wire is firmly held. 
There should be about a 5 cm 
sag in the middle. Fasten the 
copper wires (F) to each 
terminal in the same manner. 
Connect clips to these wires. 
For power use a transformer 

(PHYS/VII/A2) wired to a wall 
outlet [Note (iii) ] , or a heavy- 
duty battery. 



(i) Prepare the jar, bottle, light bulb, etc., to be cut by etching a continuous 
line around the glass (I/Fl) . Connect the cutter to a power supply until the 
wire is hot, then place the etched line on the hot wire, Hold the glass in this 
position until it cracks along the healed portion. Then rotate the glass to heat 
another portion of the etched line. Continue this procedure until the crack has 



-26- 



circled the glass and the two sections separate. 

(ii) The broken edges of the glass can be smoothed by rubbing them with wire 
gauze or wet sandpaper (emery paper) . 

(iii) If the wire cutter is used with a wall outlet (120 volt) then a transformer 
must be employed to bring the voltage down to 12 volts, 3 amps. The cutter can 
also be used with a standard 12 volt automobile battery. However, using a 
battery reguires more time for heating the etched line, since the wire does 
not get as hot . 



-27- 



Strinq Heating 

a. Materials Required 
Bottle, jar, or light bulb 

String 

Container of cold water 

Alcohol, kerosene, or turpentine 

Tape or paper 

Glass cutter or triangular file 

b. Procedure 






-Scratch 
"String 



Wet Paper Cooling 

a. Materials Reguired 

Bottle, jar or light bulb 

Alcohol or gas burner, or candle 

Triangular file or glass cutter 

Blotting paper or wrapping paper 

String 

Container of cold water 



Prepare the bottle or jar as 
described in I/Fl above. After 
the paper or tape guide has been 
removed, tie a piece of string 
or cord which has been soaked 
in a flammable liquid around 
the bottle about . 5 cm below 
the scratch. Liqht the string 
with a match, and as soon as 
the flame dies down, pour cold 
water on the bottle. The sud- 
den change from hot to cold will 
break the bottle along the 
scratch. This process may have 
to be repeated to break thick 
glass. Smooth the cut edge of 
the glass as described in 
Note (ii) above. 



-28- 



b. Procedure 




Scratch 



Paper 



Wind a strip of blotting paper, 
paper towel, or wrapping paper 
about 5 cm wide around the 
bottle at one side of the line 
to be cut. Wrap the paper at 
least 0.5 cm thick and then tie 
the paper with string or rubber 
bands. With the file or glass 
cutter, scratch a line com- 
pletely around the bottle at 
the top edge of the paper. Put 
the bottie into cold water 
until the paper is soaked 
(about five minutes) . Remove 
the bottle from the water, and 
rotate it in a horizontal posi- 
tion, with the scratch on the 
glass just above a small, fine 
flame. Continue this for four 
or five minutes. If the 
bottle has not dropped apart, 
put the bottle vertically into 
the water. The bottle should 
break into two parts along the 
scratch. If it does not, 
repeat the heating and cooling 
until it does. It is crucial 
that the flame be very small so 
as to heat a minimum of glass 
on either side of the scratch. 



c. Notes 

(i) To drill a hole in a glass bottle or jar, follow the procedure outlined 
for drilling in a glass sheet (I/E2) . 



-29- 



G. STOPPERS 

Stoppers for use in scientific apparatus are commonly manufactured of either cork 
or hard rubber. 

Rubber Stoppers 

Rubber stoppers are more durable for general use than cork stoppers. They are 
available in standardized sizes, and are manufactured with no holes as well as with 
one, two or three holes. Although they tend to react with organic solvents like 
gasoline, they provide an excellent seal in most cases and can even be sterilized. 
(BI0/VII/A2) . If a stopper with holes is specified in the directions for a piece of 
apparatus, use rubber stoppers with pre-drilled holes if at all possible. If it 
becomes necessary to drill a hole or holes in a rubber stopper, consult the notes 
following the discussions of boring and drilling holes in cork stoppers(I/Gl and 
G2) . 

Cork Stoppers 

Cork stoppers, while generally less expensive than those made of rubber, are not 
as suitable for general use. They tend to lose their shape after long use, are not 
available with holes pre-drilled, tend to absorb reagents, and cannot be adeguately 
sterilized. Should it be necessary to bore a hole or holes in a cork stopper for the 
insertion of glass tubing, one of the following methods may be employed. 



Gl, Cork Boring 

a. Materials Required 
Cork stopper 

Set of hand cork borers 

b. Procedure 







■* Cleaning 

Rod 



ts— >>. , Cutting 
\~s* Edge 



If a set of hand cork borers in 
graduated sizes is available 
from a scientific supply house, 
choose a cork borer of the same 
or slightly smaller diameter as 
the glass tubing that is to go 
through the cork. 

The cork borer set generally is 
supplied with a rod to clean 
pieces of cork out of the 
borer. Soften the cork by 
wrapping it in a piece of 
paper and rolling it gently on 
the floor under your foot. 

With one hand, hold the cork 
firmly on the table or bench, 
wide end up. With the other 
hand, place the cutting edge of 
the cork borer in the center of 
the cork. Then with a gentle 
twisting motion on the cork 
borer, bore into the cork until 
the tool is about halfway 
through the cork. 

It is not necessary to push hard; 
but twist gently with light 
pressure. Remove the cork borer 
from the cork and push out small 
pieces of cork inside it with 
the cleaning rod. 

Turn the cork over and repeat 
this process until there is a 
hole through the cork. 



-31- 



c. Notes 



(i) Iftwo holes are desired, the first must be bored near one edge of the cork 

in the manner described above. 
The second hole is then bored 
in the same way. A guide line, 
drawn around the middle of 
the cork, is helpful in deter- 
mining the positions of the 
two holes. 




(Ii) This method is suitable for boring holes in rubber stoppers. However, the 
stopper as well as the end of the boring tool should be lubricated with glycerine. 



-32- 



G2. Cork Drilling 

a. Materials Required 
Cork stopper 

Round file 

Cloth, or wooden handle 

Burner 

Brick or asbestos pad 

b. Procedure 




Soften the cork as described in 
I/Gl above. Hold the cork, 
wrapped in cloth or clamped in 
pliers, securely against the 
brick or asbestos pad with one 
hand. Hold the file, wrapped 
in cloth or in a wooden handle, 
by its four-sided end in the 
other hand. Heat the round end 
of the file in the burner flame. 
Remove the file from the flame 
when it glows red hot, and push 
it gently into the center of the 
cork. Push it only about half- 
way through the cork, then 
remove it . 

Turn the cork over, reheat the 
file, and make another hole to 
meet the first one. 

Allow the file to cool, then 
enlarge the hole to the desired 
size by gentle filing. 



c. Notes 



Care must be taken not to overheat the file, or it may set the cork on fire. 
Should this happen, blow the flame out quickly. 

(ii) Two holes can also be made through the cork with this method. 

(iii) Very small holes can be made in corks in the same manner by using heated 
wire. 



-33- 



(iv) If a hand drill or electric drill is available, holes can easily be bored 
by using either a regular drill bit or the round file as the drill bit, The cork 
must be rigidly held in a vise. For an accurate hole, just as with the other 
methods of drilling, a hole should be drilled halfway through the cork from each 
side, to meet in the center of the cork. 

(v) It is possible to drill holes in rubber stoppers with a hand drill or 
electric drill, but the hot file method will not work in rubber stoppers. 

G3 . Inserting Glass Tubing Through a Stopper 
a. Materials Required 
Glass tubing 
Burner 

One-hole cork or rubber stopper 
Cloth 
Glycerine 



b. Procedure 




Hold Here 




Fire polish the end of the tube 
that is to go into the stopper. 
Allow it to cool. Hold the 
tubing about 2 - 3 cm from the 
fire-polished end in one hand. 
Lubricate this end of the tube 
with glycerine. Hold the 
stopper in the other hand. 
Gently and carefully push the 
tube into the stopper with a 
twisting motion. Do not use too 
much force or the tube will snap. 

When pushing a piece of bent 
tubing into a stopper, always 
hold the tube between the bend 
and the stopper. Do not push on 
the bend; it is weak and will 
break easily. 



c. Notes 

(i) This is a technigue that, if improperly done, can be quite dangerous. 
When done correctly, however, it is quite safe. 



-34- 



1 1 . BURNERS 



These have been grouped according to the type of fuel used. 



A. SOLID FUEL BURNERS 



These are the simplest burners to make, and include candles as well as charcoal 
burners . 

B. LIQUID FUEL BURNERS 

These include several types of alcohol burners. 

C. GAS BURNERS AND SYSTEMS 

These are functional items, providing the cleanest, most intense heat. However, 
they are somewhat more sophisticated for production purposes, 



-35- 



A. SOLID FUEL BURNERS 



Al . Candle Burner 




(1 ) Container 



(2) h 



eat Source 



a. Materials Required 
Components 

(1) Container 

(2) Heat Source 

b. Construction 

(1) Container 

(2) Heat Source 



c. Notes 



Qll I tems Required 

1 Shallow Tin Can (A) 

3 Household Candles (B) 



Dimensions 

5 cm diameter or 
larger 

Varies 



Select a tin can (A) with low 
sides . 

Melt the wax at the base of the 
candles (B) and place them at 
equal intervals within the con- 
tainer. 



(i) The intensity of the heat produced may be increased by increasing the 
number of candles, but the total intensity is low. 

(ii) The efficiency of a candle burner may be improved by collecting all the wax 
that melts into the container and using it again with new wicks made from soft 
string. 

(iii) The candle flames tend to deposit soot on the surface of whatever is being 
heated. 



-36- 



A2. Charcoal Burner * 



(1) Can 



t ' 
i 




a. Materials Required 
Components 

(1) Can 

b. Construction 

(1) Can 



Qli I tems Required 

1 Empty Metal Can (A) 



Bend Up 
Triangles 




■Cut Here 



Dimensions 

10 cm diameter or 
larger 



Remove top from can (A) . Approx- 
imately 4 cm from the bottom of 
the can, mark off triangular 
windows all around. 

With shears, cut along the 
sloping sides of each triangle 
to make the windows . Do not cut 
along the base line (horizontal 
edge) of the triangle. 

Bend the triangles up to form a 
tray. 



*Adaptedfrom UNESCO, Source Book for Science Teaching_ , (Paris: UNESCO, 1967), 
pp 34-35. 



-37- 



c. Notes 

(i) The holes permit air to circulate freely to the burning charcoal. 

(ii) Comments from users of the charcoal burners indicate that they are hard to 
start. Also, once started, they present a considerable fire and carbon monoxide 
risk. 



Bl, Simple Alcohol Burner 



-3a- 



LIQUID FUEL BURNERS 




a. Materials Required 
Components 

(1) Fuel Container 

(2) Lid 

(3) Wick 

b. Construction 

(1) Fuel Container 



(2) Lid 



(3) Wick 



Qu I tems Required 

1 Glass or Metal 
Container (A) 

1 Screw Top (B) 

1 Soft Cotton Fiber 
Cord (C) 



Dimensions 

150-200 ml, approxi- 
mate capacity 

To fit fuel container 

Long enough to extend 
to bottom of con- 
tainer and to cover it. 



Make the fuel container from a 
glass or metal container (A) 
with a screw-on metal lid (B) . 
Select a container with a wide 
base to insure stability. 

Punch a hole in the lid (B) with 
a nail, making it as round and 
smooth as possible, with a 
diameter smaller than that of 
the wick to be used. 

Select a piece of cord (C) with 
soft cotton fibers. The wick 
should protrude 0.5 cm above 
the surface of the lid. 



c. Notes 

(i) If a hotter, broader flame is required, punch two holes in the lid and use 
two wicks to produce a single, broad flame. 



-39- 



(ii) The wick should be soaked in alcohol before lighting the burner. 

(iii) Methyl alcohol or denatured ethyl alcohol is the usual fuel used in the 
burner. Kerosene may also be used, but it tends to produce a smoky flame which 
blackens heated objects. 



(iv) Important: Use a stable container, 
burner will tip over easily. 



Otherwise, there is danger that the 



(v) If the burner is used for prolonged periods, overheating of the container, 
with build-up of internal pressure, is possible. 

(vi) Make certain that the wick fits tightly into the hole in the lid. Other- 
wise, it is possible for the flame to climb down the wick into the container. 

(vii) A user of alcohol burners notes that those made from 35 mm film cans have 
several advantages over larger ones made from glass containers. First, they are 

unbreakable. Second, if the 
inside is filled with cotton 
wadding (cotton wool) they are 
unspillable if knocked over. 
Also, these small film cans 
hold only enough for immediate 
use, so that evaporation losses 
are not serious . 



Film Can 




-4o- 



B2 . Modified Alcohol Burner 



(6) Cap 



(5) Wick 

„(4) Heat 
Barrier 




(3) Wick 
Holder 



(2) Fuel 
Container 



( 1) Base 



a. Materials Required 

Components QU Items Required 

(1) Base 1 Wooden Platform (A) 



Metal Lid (B) 



Dimensions 

Approximately 10 cm 
diameter (round) , or 
approximately 10 cm x 
10 cm (square) 

To fit fuel container 
bottom 



(2) Fuel Container 



(3) Wick Holder 



(4) Heat Barrier 



(5) Wick 



(6) Cap 



1 Glass or Metal 
Container (C) 

1 Metal Lid (D) 



Metal Tube (e) 



1 Metal Disc (f) 



1 Cord (G) 



1 Ball Point Pen Top or 
Metal Tube (H) 



100-200 ml capacity 

To fit fuel container 
top (C) 

Approximately 4 cm 
long, 0.7 cm or 0.8 cm 
diameter 

5 cm diameter or 
larger 

Approximately 10 cm 
long, 0.5 cm or more 
in diameter 

To fit wick holder 



-41- 



b. Construction 



(1) Base 




Lid (B) 



Nail 



Base (A) 



Nail the metal lid (B) (with a 
diameter equal to that of the 
fuel container) to the round or 
square wooden base (B) . 



(2) Fuel Container 



(3) Wick Holder 



(CD 



Select a qlass or metal con- 
tainer (C) with a screw-on lid 

(D). 

Make the wick holder from a 
metal tube (E) about 4 cm lonq 
x 0.7 or 0.8 cm internal 
diameter, or roll a piece of 
sheet metal (4 cm x 2.5 cm) 
into a tube. 




(4) Heat Barrier 



Seams 




Seam 



Drill a hole in the fuel con- 
tainer lid (D) large enough to 
allow insertion of the wick 
holder. Insert the wick holder 
so that it penetrates about 
1 cm into the container. Solder 
the seam along the tube and 
between the tube and the lid. 

Cut the metal disc (F) from 
metal sheeting, or use a tin can 
top. The disc should be 
slightly larger than the fuel 
container lid (D) . 

Drill a hole in the center of 
the disc large enough to allow 
insertion of the wick holder 
(E) . Insert the wick holder so 



-42- 



(5) Wick 



(6) Cap 



that about 1.0- 1 . 5 cm pro- 
trudes above the disc. Solder 
the seam between the heat 
barrier and wick holder. 

Make the wick from a piece of 
cord (G) or rope with soft 
cotton fibers. Insert the wick 
into the wick holder. Trim 
the wick with scissors so that 
about 0.4 - 0.5 cm protrudes 
above the top of the wick 
holder. 

Use a ball point pen top (H) as 
a cap or make a metal cap large 
enough to fit snugly over the 
wick holder when the burner is 
not in use. The cap prevents 
evaporation of the alcohol. 



c. Notes 



(i) The design of this burner overcomes the major hazards of the simple alcohol 
burner (I I/Bl) . 

(ii) This 'design can be modified to produce a wide flame that is particularly 
useful for working with glass. All parts of the design are the same, except for 
the shape of the wick, wick holder, and cap. 

For the wick holder, cut a piece of metal sheeting about 5 cm x 4 cm. Bend 
it into a flat tube about 2 cm wide and 0.5 cm deep. Solder the seam. Install 
this wick holder in the fuel container lid and heat barrier just as in the previous 
design. For the wick, use flat cotton webbing about 2 cm wide and 10 cm long, or 

braid (plait) a flat wick from 




6) Gap 

(5) Wick 

\4) Heat Barrier 

(3) Wick Holder 



(2) Fuel 
Container 



six to ten strands of cotton 
cord or string. Make a cap from 
metal sheeting to fit snugly 
over the wick holder when the 
burner is not in use, 



(1) Base 



-43- 



C. GAS BURNERS AND SYSTEMS 



CI. Fuel System for Gas Burner * 



(3) Fuel Unit 




(1) Pressure Unit 



(6) Connecting 
Tubing 



(5) Burner 



a. Materials Reguired 
Components 
(1) Pressure Unit 



(2) Clamp 

(3) Fuel Unit 



Qll I tems Required 

1 Metal Drum (A) 

1 Metal Drum (B) 

3 Wood (C) 
3 Bolts (D) 



1-Hole Stopper (E) 

Glass Tubing (F) 

Container and Sand (G) 
Screw Clamp (H) 
Metal Can (I) 

2-Hole Rubber Stopper (J) 



Dimensions 

Approximately 2 6 
liter capacity 

Approximately 16 
liter capacity 

3 cm x 2 cm x 65 cm 

0.5 cm diameter, 

4 cm long 

Approximately 2 . 5 cm 
diameter (large end) 

. 5-0 . 7 cm diameter, 
10 cm long 

Approximately 6 kg 

IV/A5 

4 liter capacity, 
approximately 

To fit opening in can 



*Adapted from C. S. Rao (Editor), Science Teachers' Handbook, ( Hyderabad, India: 
American Peace Corps, 1968), pp 140-141. 



-44- 



(4) Safety Tank I 

1 
1 

1 

(5) Burner 1 

(6) Connecting Tube 3 

b. Construction 



(1) Pressure Unit 



Glass Tubing (K) 

Glass Tubing (L) 

Narrow-neck Bottle (M) 

2-Hole Rubber Stopper (N) 
Glass Tubing (0) 

Glass Tubing (P) 

Gas Burner (Q) 

Plastic or Rubber Tubing 
(R) 



. 5 cm diameter, 10 cm 
longer than height 
of can 

. 5 cm diameter, 10 cm 
long 

500 ml capacity, 
approximately 

To fit bottle 

. 5 cm diameter, 10 cm 
longer than height of 
bottle 

. 5 cm diameter, 10 cm 
long 

II/C2 

Approximately 1 cm 
diameter, and approxi- 
mately 1 meter long 




Wood (C) 



Bolts (D) 



Drum (A) 



Select two metal drums (A,B) of 
approximately the same depths, 
but different diameters, so 
that one drum (B) will fit 
inside the other (A) . Each drum 
should have one end open. Bolt 
the three pieces of wood (C) 
to the larger drum (A) with the 
bolts (D) so that the space 
between them is just sufficient 
to allow the smaller drum (B) to 
slide down easily between them. 



-45- 




Sand Can(G) 



Glass 
Tube (F) 



Stopper (E) 



-Drum (B) 



Drum (A) 



Use an alcohol lamp to make a 
90' bend in the middle of the 
glass tubing (F), or cut a 
shorter piece of straight tubing. 
Fit the glass tube into the 
stopper (E) . Bore a hole near 
one side in the bottom of the 
smaller drum (B) . Insert the 
stopper into this hole. 

Fill the larger drum (A) with 
water egual to the volume of 
the smaller drum. 

Fit the smaller drum, open side 
down, between the wooden up- 
rights of the larger drum. 

Push down on the upper (air) 
drum (B) . It should slide down 
into the lower drum (A) . Air 
should be felt escaping from the 
glass tubing (F) . 

Place a can or bucket filled 
with sand (G) on the air drum, 
as a weight . 



(2) Clamp 




Use the screw-type clamp (H) or 
any standard screw-type clamp 
to control the air pressure 
from the fuel tank. 



-46- 



(3) Fuel Unit 



Glass 
Tube (K) 




Glass 
Tube (L) 



2-Hole 



Stopper (J 



Metal 

Can (I) 



Gasoline 



Fuel Unit 
(Cross-section) 



(4) Safety Tank 



Stopper *- 

(N) 



Glass 
Tube (0) 




Glass 
Tube (P) 



Bottle (M) 



Make the fuel container from a 
metal drum (I) or can with a 
single outlet, rather than a 
lid. Fit the drum with a two- 
hole rubber stopper (J) . 

Make a 90' bend about 5 cm from 
one end of the longer piece of 
glass tubing (K) , or use a 
slightly shorter piece of 
straight tubing. 

Make a 90" bend in the middle 
of the short piece of glass 
tubing (L) . 

Insert both pieces of tubing 
into the stopper as illustrated. 

Fill the can about 3/4 full of 
gasoline (petrol) . 

Select a glass or metal con- 
tainer (M) with a narrow neck. 
Fit the container with the 
two-hole rubber stopper (N) . 

Bend both, pieces of glass 
tubing (0,P) as described above, 
and insert each into the stopper 
as illustrated. 

Fill this container about 1/3 
full of water. 



(5) Burner 



(6) Connecting Tubing 



Construct a Bunsen burner (Q) 
as described in the next sec- 
tion (II/C2) . 

Use flexible tubing (R) (rubber 
or plastic) to connect the 



-47- 



apparatus as illustrated. 

Connect the tubing from the 
Pressure Unit (1) with the long 
glass tube of the Fuel Unit (3) . 

Connect the tubing from the 
short glass tube of the Fuel 
Unit (3) with the long glass 
tube of the Safety Tank (4) . 

Attach the connecting tubing 
from the short glass tube of 
the Safety Tank (4) to the 
Bunsen burner (5) . Take care 
to see that the tubing is not 
kinked anywhere . 

When all components are 
assembled and correctly con- 
nected, remove the weight and 
stopper from the upper (air) 
drum. Lift the drum until its 
lower edge 3s just below the 
water level in the lower drum. 
Replace the stopper and check 
to see that it is tight, and 
replace the weight on top of 
the drum. 



c. Notes 



(i) As the air drum sinks into the water of the lower drum under its own weight 
and the pressure of the weight on top, the air thus displaced is driven into the 
fuel drum and bubbles up through the petrol. The petrol evaporates as the air 
passes through it, and the air-gas mixture is driven through the water in the 
safety tank to the burner. 

(ii) This system is potentially dangerous because the petrol-air mixture present 
from the fuel tank is an explosive mixture, but several safety precautions have 
been incorporated into the design. 

The greatest safety factor is the needle valve in the burner; even when the 
burner occasionally "backfires" (the flame jumps down from the end of the burner 
tube to the needle opening) the flame is very unlikely to move back through the 
needle's narrow opening. In the unlikely event that a flame should move back down 



48- 



the tubing, the safety tank prevents it from reaching the fuel drum. As a further 
safety measure in the safety tank, the stopper should be snug, but not jammed 
tightly into the neck of the container. Thus, should the flame move back into the 
safety tank, it will be more likely to blow the stopper out of the tank than to 
blow the tank apart. 

Despite the built-in safety precautions, however, feedback comments suggest 
extreme care in the use of this system. 

(iii) In the system described here, a glass bottle, encased in a cage of wire 
mesh for additional safety, was used as a water tank. This made it possible to 
observe the rate of bubbles in the water, an indicator of the pressure in the 
system. A fairly rapid rate of bubbles, about 100 or more per minute, was neces- 
sary to produce a burner flame 3 - 4 cm high. It is recommended, however, that 
once the bubbling rate is established, a metal safety tank of similar size be 
substituted for the glass bottle. 

(iv) A weight of approximately 5.5 kg on an air drum with an area of 4 90 cm2 
(diameter 25 cm) provided 11 g/cm2 pressure to run the Bunsen burner described in 
the following section (II/C2) for about a half-hour. 

(v) The system and dimensions described here constitute a small, laboratory 



version suitable for running one Bunsen burner. 



To Fuel 
Unit 




For a larger system, the same 
components and principles apply, 
but experimentation on the 
details of construction will be 
necessary. For example, a 
larger pressure system, with a 
large, heavy oil drum for the 
upper drum would provide pres- 
sure for a longer period of 
time and might not reguire a 
weight on top. An air pump 
could be added to fill the drum 
with air without lifting it. 



Air Pump 



-49- 



C2. Gas Burner 



1) Burner Tube 




(2) Air Control Sleeve 

(3) Gas Valve 



(4) Base 



(5) Gas Tube 



a. Materials Required 
Component s 
(1) Burner Tube 



(2) Air Control 
Sleeve 

(3) Gas Valve 



(4) Base 



(5) Gas Tubing 



Qll Items Required 
1 Copper Tubing (A) 

1 Metal Sheet (B) 

1 Hypodermic Needle (C) 

1 Adhesive Tape or 

Electrical Tape (D) 

1 Wooden Block (E) 

2 Wooden Block (F) 

1 Rubber or Plastic 
Tubing (G) 



Metal Tube (H) 



Dimensions 

10.5 cm long, 
1 cm diameter 

3 cm x 3.5 cm 



18 gauge (0.125 cm 
outside diameter) 

Approximately 1 cm 
wide, 15-30 cm long 

10 cm x 10 cm x 2 cm 
10 cm x 5 cm x 2 cm 

Approximately 15-20 cm 
long, approximately 
0.6 cm internal 
diameter 

3 cm long, 1 cm 
diameter 



*Adapted from C. S. Rao (Editor), Science Teachers' Handbook, (Hyderabad, India: 
American Peace Corps, 1968), pp 138, 141. 



■50- 



b. Construction 
(1) Burner Tube 



^~D 



Air Holes 



(2) Air Control Sleeve 



Metal 
Sheet (B) 





(3) Gas Valve 




Drill two holes on opposite 
sides of the copper tube (A) 
about 2 - 2 . 5 cm from one end. 
Enlarge the holes to an oval 
shape, about 1 cm long x 0.6 cm 
wide . 

Lay the metal sheet (B) flat on 
a table. Lay the burner tube 
on it with the end of the tube 
with the holes in it about 1.0 
cm from the 3 . 5 cm edge. 
Actually, the holes themselves 
should be 1.0 cm from the 3.5 
cm edge. 

Use a pencil to trace the out- 
line of one of the holes in the 
tube onto the metal sheet. Cut 
this hole out. lineWrap the metal 
sheet around the burner tube 
until it forms a cylinder. 
Align the hole in the metal 
sheet with one of those in the 
tube. lineTrace the outline of the 
other hole in the tube onto the 
metal sheet. Remove the metal 
sheet, and cut out the second 
hole. 

Reroll the air control sleeve 
and place it in position on the 
burner tube. 

Cut the top off the hypodermic 
needle (C) so that about 1 cm 
of the needle remains. File the 
linecut end of the needle open. 



Needle 
Base 



-51- 



pn 



Q 



n 






Burner 
' Tube 

_Air Control 
Sleeve 

_Needle (C) 



Base with 
" Tape (D) 



Wrap the adhesive tape (D) or 
electrical tape around the 
needle holder until the base of 
the needle will fit tightly into 
the bottom of the burner tube. 
The open end of the needle 
should be near the middle of 
the air holes. 



Side View 



(4) Base 




Wood (E) 



Drill a hole approximately 1.2 
cm in diameter in the center of 
the square piece of wood (E) . 
Enlarge the hole with a file to 
tightly hold the burner tube 
and gas tubing in place. 

Nail the two rectangular pieces 
of wood (F) to the square to 
form the sides of the base. 



Wood 



(5) Gas Tubing 




Rubber 
Tube (G) 



Metal 
Tube (H) 



Connect one end of the plastic 
or rubber tubing (G) to the 
bottom of the burner tube. 
Then push the burner tube 
through the hole in the top of 
the base. It should fit snugly 
in place and should not wobble. 

Pass the other end of the gas 
tubing through one open side of 
the base. Ins ert the small 
metal tube (H) into the open end 
of the gas tub i ng. 

Connect tubing from the gas 
supply to this metal tube. 



-52- 



c. Notes 

(i) This burner has been tested with both commercially supplied natural gas 
and with the gas generating system described in the previous section II/C1. 

(ii) When the burner is lit, the air control sleeve can be used to control the 
nature and intensity of the flame. The sleeve is closed when its holes and the 
holes in the burner tube. are not Mned up with each other. No air enters the 
burner tube. The flame is smoky, yellow, and glowing. It gives little heat. The 
absence of air prevents the gas from being completely burned. 

When the sleeve is turned so that its holes and those of the burner tube 
are partly lined up, some air enters the burner tube. The flame is almost color- 
less, and does not glow. It is quite hot. The gas is more completely burned in 
this flame because of the presence of some air. 

When the holes of the air control sleeve completely match those in the 
burner tube, the maximum amount of air enters the burner tube. 

This produces a very hot, roaring flame with a bright blue center cone. 
The gas is completely .burned, producing the hottest flame, because there is 
plenty of air entering the burner tube. 



Purplish Cone - hot part of the flame, called the 

I 'l l i ii 
0X1 01 Zing Tlame . Combustion of the gas is most complete. 

Hottest part of the flame just above the inner blue 
cone of flame. 

cone not as hot as the outer cone because there 




is insufficient oxygen mixed with the gas to completely 
burn it. Called the reducing flame because it can take 
oxygen away from some oxides. 



Dark cone 



not a flame at all. It is filled with a 



mixture of unburned gas and air coming from the barrel. 



Use a blue flame, about 4 cm high, for glass-working operations and most other 
heating operations . Adjust the gas supply and air control sleeve of the burner 
to produce a quiet blue flame with distinct cones. 

(iii) In use this burner produced an excellent flame suitable for working soft 
glass and for blowing small bulbs in 0.3 cm and 0.5 cm soft glass tubing. However, 
the burner tube tended to heat up after a few minutes use. The larger diameter 
burner, of slightly more complex design, avoids this difficulty to some extent. 

(iv) If a larger diameter tube (e.g., 1.5 cm diameter) is used for the burner 
tube, several alterations must be made to the design of the burner. First, a 
larger diameter syringe needle is needed (16 gauge, 0.15 cm outside diameter), and 



-53- 



it must be cut off shorter, i.e., . 5 cm rather than 1.0. Secondly, the end of 
the burner tube must be flattened slightly to restrict the flow of air/gas mixture 
through it. Thirdly, the connection between burner tube, gas valve, and gas tube 
must be altered. One way in which this can be done is to drill a hole 1.0 cm in 

diameter through a cork. 



Tj ^urn er Tube 

If (Flattened 



Needle 




Base 



Metal 
Tube 



Cross Section 



Enlarge the hole at one end to 
1 . 5 cm diameter, and 1 . 5 cm 
deep. Insert a 1.0 cm diameter 
piece of metal tubing through 
the hole and place a short 

(1.0 cm) piece of rubber tubing 
on the end of it. Insert the 
needle into the rubber tube 

(the base may have to be built 
up with tape) . Insert the 
burner tube into the enlarged 
hole in the cork. Make certain 
the fit is tight. Finally, 
insert the cork into the hole 
in the base, put the air control 
sleeve in place, and attach the 
gas tubing. 

If, when this burner is in use, 



the flame should tend to blow itself out because the tube opening is too wide, 
decrease it further by pinching with pliers. 

(v) It must be noted that various components of the burner design are dependent 
on the diameter of the burner tube. These include burner tube length, size of 
the air holes, gauge and length of the needle, width at the top of the tube, and 
various connecting devices such as metal and rubber or plastic tubing. For 
example, if the diameter of the burner tube is increased, the diameter of the 
needle used and the length of the tube must also be increased, but the size of the 
opening at the top of the tube must be decreased. Therefore, if tubing of a size 
different from those described here is used, experimentation with the other com- 
ponents will be necessary in order to construct a working Bunsen burner. 



-54- 



13. Wing Tip 




(1) Wing Tip 



a. Materials Required 
Components 
(1) Wing Tip 



QU I tems Required 
1 Metal Sheet (A) 
1 Metal Sheet (B) 



Dimensions 
6 cm x 4 cm 
6 cm x 4 cm 



b. Procedure 












(1) Wing Tip 






0.8 






\ \L 


4 


r| 




xVr 




1 






' /■ 




\ N 
\ \ 
\ \ 
\ \ 
\ \ 


2 


/ / 
/ / 
/ / 


/ Metal 
Sheet (A) 




1 
1 1. 

i 


V, 


1.0 
JL 






U-4. 


< »l 


of Cii 




0.5 


y 


X 0.5 


■cumf erence 








of I 


3urner 


Tube 



Measure the circumference of 
the burner tube. Draw and cut 
out a paper pattern as 
illustrated. Cut one piece of 
this pattern from the metal 
sheeting (A) . Cut on the 
solid lines. Bend on the dotted 
lines . 




/ / Metal 
/ / Sheet (B) 



Cut another piece from the 
metal sheeting (B) , but trim 
the flaps on the wing to 0.4 cm. 
Cut on the solid lines. Bend 
on the dotted lines. 



-55- 




Metal (A) 



Metal (B) 



Burner Tube 



Bend the wing flaps on piece 
(B) at 90°. Bend the wing 

flaps of piece (A) around the 

outside of the flaps on (B) . 

Pinch the flaps on (A) to hold 
(B) in place. 

Place the wing tip on the 
burner tube, such that the 
wing extends above the burner 
tube. 

Bend the support strip flaps of 
(B) and (A) to fit snugly 
around the burner tube. Small 
holes left at the corners of 
the flaps will not affect the 
wing tip's performance. 



c. Notes 

(i) The wing tip is an accessory used with the gas burner when a wide flame is 
desired. It is especially useful for working with glass. 



-56- 



III MEASURING APPARATUS 

A. DEMONSTRATION DEVICES 

These devices demonstrate thermal expansion of liquids and solids, 

B. VOLUMETRIC MEASURES 



These are all measures of liquid volume and ranqe from sinqle volume measures 
like volumetric flasks to multiple measures such as measuring cylinder. Also included 
under this heading is the specific gravity bottle. 



-57- 



A. DEMONSTRATION DEVICES 



Al . Demonstration Thermometer 




"(1) Thermometer 



a. Materials Required 
Components 
( 1 )Thermometer 



b. Construction 



(1) Thermometer 



Qu I tems Required 

1 Pill Bottle (A) 

1 Pill Bottle Cap (B) 
1 Glass Tubing (C) 



Dimensions 

7 cm high, 3 cm 
diameter 

To fit pill bottle (A) 

25 cm long, . 5 cm 
outside diameter, 
. 3 cm inside 
diameter 



Make a hole in the pill bottle 
cap (B) (or a suitably sized 
cork) through which the glass 
tubing (C) is inserted. 

Be certain the seal is airtight 
(it may be necessary to use 
glue to insure an airtight seal) 



Fill the bottle (A) completely 
with water or other liquid. 
Force the cap or cork down onto 
the mouth of the bottle so that 
some liquid is forced up into 
the tube and the rest of the 
excess liquid spills over the 
side of the bottle where it is 
wiped away. Some liquid must 
rise up far enough into the 
tube so that it can be seen. 



c. Notes 



(i) This thermometer is used simply to demonstrate the expansion of a liquid 
as it is used in standard thermometers. Putting the demonstration thermometer 
into a 60°C water bath will cause the level of the water in the tube to rise about 
2 cm. 

(ii) Be certain to eliminate all air bubbles from the bottle unless it is 
desirable to show the effect of having air trapped in the bottle. 



A2. Bi-Metal Strip 



-59- 




(2) Handle 



(1) Bi-metal Strip 



a. Materials Required 

Components Qu I tems Required 

(1) Bi-metal Strip 1 Steel Strapping (A) 

1 Aluminum Sheet (B) 

9 Nails (C) 



(2) Handle 



1 Wood (D) 



Dimensions 

20 cm x 1.2 cm x 
0.8 cm 

20 cm x 1.2 cm x 
0.6 cm 

#4 d (0.2 cm diameter 
with large heads) 

1 . 5 cm x 2 . cm x 
10 cm 



b. Construction 

(1) Bi-metal Strip 



Y 



20 



eoooeoo o o 
_i i_ 






/ 



Metal Strip (A,B) 



Cut Here 



* — J Nail (C) 



0.5 



Hammer This 
r End Down 



jL 



Nail Head 



Side View 



Hold the two pieces of metal 
(A,B) tightly together, and 
drill nine holes through both 
at 2 cm intervals beginning 
1 . cm from one end. These 
holes must be very slightly 
larger in diameter than the 
nails (C) used. 

Cut the head off each nail (C) 
with a hacksaw, chisel, or tin 
snips so that the portion with 
the head is about . 5 cm long. 
Push the nails through the 
holes in the two strips (A,B) 
and hammer down the cut ends to 
rivet the two strips together. 
It is best to begin by riveting 
the strip at its center and 
moving out toward each end at 
the same time. The strips should 
be firmly held together all 



-60- 



(2) Handle 



Zi 



>'-5V 



=r 



Notch 



along their length. 

Make a narrow notch in one end 
of the wood (D) the width of 
a saw blade. This notch ought 
to be about 1 . 5 cm deep. Insert 
the end of the bi-metal strip 
into this notch to complete the 
device. 



c. Notes 



(i) This device is used to demonstrate the fact that metals expand when they 
are heated. When the bi-metal strip is held in a flame, it will bend in the 
direction of the steel since the aluminum expands more than does the steel. 

(ii) Different combinations of metals (e.g., copper and steel, brass and alu- 
minum, etc.) can be used with the same results. 

(iii) The metal strips may be soldered together as opposed to riveted. Melt a 
thin layer of solder onto the surface of one of the two strips. Lay the other 
strip on top of it and hold the soldering iron down on both strips until the 
solder melts between the two strips. Keep the two strips pressed together with a 
screwdriver or other object to prevent them from coming apart before the solder 
cools. Repeat this process until the two strips are soldered all along their 
lengths. (Note: This procedure will not work if aluminum is used as one of the 
metals unless special solder is used.) 



-61- 



B. VOLUMETRIC MEASURES 



Bl. Burette 



LI 



(1) Tube 



2 — 



(2) Clamp 



a. Materials Required 
Components 
(1) Tube 



Qu I tems Required 
1 Glass Tube (A) 

1 Glass Tube (B) 

1 Glass Tube (C) 

1 Rubber Tubing (D) 



Dimensions 

45 cm long, 1.3 cm 

outside diameter, 

1 . 1 cm inside diameter 

4 cm long, . 7 cm 
outside diameter, 
0.5 cm inside 
diameter 

9 cm long, . 7 cm 
outside diameter, 
0.5 cm inside 
diameter 

10 cm long, 1.0 cm 
outside diameter 



(2) Clamp 



Pinch Clamp (E) 



IV/A4 



-62- 



b. Construction 
(1) Tube 



p^u 



/*- 



Rubber 
Tube (D) •< 



I I 



-Glass Tube (A) 



>• Glass Tube (B) 



■S 



u 



> 



Glass Tube (C) 



Insert the glass tubing (B) into 
the end of the rubber tubing (D) 
so that the ends of both pieces 
of tubing are even. Insert 
this end into one end of the 
large glass tubing (A) for a 
distance of about 1-1.5 cm. 
If the seal between the rubber 
and large glass tubing is not 
watertight, use thin rubber 
sheeting (e.g., balloon mater- 
ial) to fill in the gas. Seal 
this joint with glue to insure 
a watertight fit. Draw out one 
end of the remaining piece of 
glass tubing (C) in a flame to 
form a narrow neck. Break off 
the neck, and fire polish the 
end of the tube. Insert the 
wide end of this tube into the 
end of the rubber tubing (D) 
for a distance of about 2 cm. 
Check the tube now for water- 
tightness . 



Detail 



(2) Clamp 



Use the clamp (E) to regulate 
flow in the burette. Be sure 
the clamp is large and strong 
enough to completely shut off 
flow from the burette. 



c. Notes 



(i) The most common use of the burette in chemistry is in doing titrations. 



-63- 



Quite often they are used in pairs, and must always be supported by a stand. 

(ii) Each burette needs to be fitted with a scale. Attach a long, thin strip 
of paper to the burette tube with transparent tape. Fill the burette from a known 
source (e.g., a plastic syringe) one milliliter at a time and mark the level of 
the meniscus on the paper. Place the "0" mark in such a way that several milli- 
liters of liguid will still remain in the burette when "0" is reached as this will 
insure greater accuracy. 

(iii) A glass bead just slightly larger than the internal diameter of the rubber 

tubing may be used in place of 



Glass Tube 



Glass Bead 



Rubber Tube 



Glass Tube 



the pinch clamp. Push the bead 
into the rubber tubing before 
inserting the glass nozzle. 
The bead will seal the rubber 
tube. To dispense liquid from 
the burette, squeeze the tube 
between thumb and forefinger 
at the location of the head. 



\J 



Cross Section 



(iv) Because of the use of rubber tubing in this burette, it is not suitable for 
use with strong corrosives that attack rubber. 



-64- 



BZ. Measuring Glass 






/ \ 



— 3oo 



(1) Bottle 




a. Materials Required 
Components 

(1) Bottle 

b. Construction 

(1) Bottle 



q u Items Required 
1 Glass Bottle (A) 



Dimensions 
Variable 

Use a glass bottle (A) with 
straight sides and a flat 
bottom. Make graduations by 
calibrating the bottle using a 
known source. The graduations 
may be tape, paint, or scratches 
on the glass itself. 

c. Notes 

(i) Inaccuracies may occur due to transfer of liquid from the known source, 
failure to wait for liquid to "settle" before making calibration marks, and human 
error in marking exact height of liquid. However, for most purposes these 
measuring glasses are adequate. 

(ii) Graduations may be made every 10, 25, 50, or 100 ml, depending on the size 
of the bottle and the uses to which it is to be put. 



-65- 



c. Notes 

(iii) If the bottle is narrow enough in diameter, the graduations may be made 
closer together (i.e., every milliliter), but the accuracy will not approach that 
of a commercially made graduated cylinder. 



-66- 



B3 . Dropper 



fee 



Z> 



(1) Dropper 



a. Materials Required 
Components 

(1) Dropper 

b. Construction 

(1) Dropper 



Qu I tems Required 
1 Dropper 



Dimensions 
BI0L/II/A6 

Construct the dropper as 
described in BI0L/II/A6. 



c. Notes 

(i) Since commercial droppers are usually readily available and inexpensive, 
this item is as easily purchased as it is improvised. 



-67- 



B4. Pipette 




(1) Pipette 



a. Materials Required 
Components 

(1) Pipette 

b. Construction 

(1) Pipette 



Q u I tems Required 
1 Transfer Pipette 



Dimensions 
BIOL/VII/A5 

Construct the pipette as 
described in BI0L/VII/A5. 



c. Notes 

(i) The pipette is used to transfer and precisely measure quantities of 
liquids . 



B5. Volumetric Flasks 




a. Materials Required 
Components 
(1) Bottle 



b. Construction 



(1) Bottle 



(2) Cap 



c. Notes 



Qu I tems Required 

1 Transparent Glass 

Bottle (A) 

1 Bottle Cap (B) 



Dimensions 
Variable 

To fit bottle (A) 

Select any common qlass bottle 
(A) with a narrow neck. 

Use a cap seal (B) which will 
be airtight to prevent leakage 
and evaporation. 



(i) The flasks must be calibrated from a known source. Put a singl e calibration 
mark on the neck of the bottle to indicate its capacity. This may be done with 
paint, tape, a scratch mark, etc. 



-69- 



B6. Specific Gravity Bottle 




(1) Bottle 



a. Materials Required 
Components 
(1) Bottle 



b. Construction 
(1) Bottle 



q u I terns Required 

1 Pill Bottle (A) 

1 Rubber or Cork Stopper (B) 

1 Glass Tube (C) 



Dimensions 

5 cm hiqh, 3 cm 
diameter 

To fit bottle (A) 

8 cm lonq, . 5 cm 
outside diameter, 
. 3 cm inside 
diameter 



Simply insure that there are 
airtiqht seals between the 
stopper (B) and bottle (A) , and 
between the qlass tube (C) and 
cork (B) . 

C. Notes 

(i) To use the specific qravity bottle, first remove the stopper and tubing and 
fill the bottle to the brim with the liquid to be measured. Reinsert the stopper, 
making sure liquid flows completely out of the end of the tubing and that there 
is no air trapped in the bottle. Wipe away the excess liquid on the outside of 
the bottle. Accurately weigh this amount of liquid and subtract the mass of the 
empty specific gravity bottle. Compare the mass of the liquid to that of an equal 



-70- 



volume of water (found in the same way) to find the specific gravity of the liquid. 

(ii) A screw-top bottle may be used instead of the stopper arrangement. Punch 
a hole in the top and seal the joint between the tubing and top with waterproof 
cement . 



-71- 



IV. SUPPORTS, STANDS, AND HOLDERS 

A. HOLDERS 

Holders are classified as small, portable, hand-held devices used to support other 
pieces of apparatus. 

B. SUPPORTS AND STANDS 



These devices are used to hold items stationery for relatively long periods of time. 



Al . Tweezers (Forceps) 



-72- 



A. HOLDERS 




(1) Tweezers 



a. Materials Required 
Components 

(1) Tweezers 

b. Construction 

(1) Tweezers 



Qu I tems Required 
1 Forceps 



Dimensions 
BI0L/II/A4 

See BI0L/II/A4 for construction 
details . 



c . Notes 

(i) Uses of forceps in chemistry operations include the handling of small 
items or radioactive materials. 



-73- 



A2 . Multi-Purpose Design Holder 



(1) Clamp 



(2) Handles 



(4) Guide 




(3) Spring 



a. Materials Reguired 
Components 

(1) Clamp 

(2) Handles 



(3) Spring 

(4) Guide 

b. Construction 



(1) Clamp 



Qu I tems Required 

2 Metal Strapping (A) 

1 Wood Block (B) 

4 Nails (C) 

1 Heavy Iron Wire 

(coat hanger) (D) 

2 Metal Strapping (E) 
4 Nails (F) 




Dimensions . 

B cm x 1.5 cm 

2cmx 4 cm x 15 cm 

0.5 cm thick x 1 cm 
long 

Approximately 30 cm 
long 

1.5 cm x 3.5 cm 

0.5 cm thick x 1 cm 
long 



Bend the two pieces of metal 
strapping (A) as indicated. 



0.5 



Cut Along 

This Line 




With a pencil and ruler, section 
the wood block (B) as shown. 
Cut two wedges and discard the 
triangular portions as waste. 



-74- 




Nails (C) 





Fasten one strapping clamp to 
the short end of each of the 
handles with the nails (C) . 



Clamp a pencil or stick of 
about 0.8 cm diameter in a 
vise, Starting at the center 
of the wire (D),coil the wire 
around the pencil. Make at 
least six turns, or a coil 
that extends beyond the width 
of the wood block (2 cm) by 
one wire-thickness on each 
side, Leave at least 9 cm of 
straight wire at each end of 
the spring. 

Approximately 4 cm from the 
spring, make a 90' bend in 
each straight section of wire, 
as shown. One cm from each 
of the first bends, make a 
second 90' bend. 




Slide the spring on to one of 
the handles as shown. 




Slide the second handle into 
place. 



■/;>- 



Bend 




N a i 1(F 




Nail 



Top View 



Trim excess wire to within 1.5 cm 
of the edge of the handle. Bend 
this remaining wire around 
handles to hold the spring in 
place. 

Lay the holder on its side. 
Slide one small piece of 
strapping under the spring as 
shown. Secure the strapping 
in place on one handle with 
one nail. Nail a second 
guiding nail into the other 
handle just at the edge of 
the strapping. Turn the 
holder over and repeat with 
another small piece of 
strapping. These guides 
keep the handles from twisting 
out of alignment. 



c. Notes 



(i) This design is based on the spring-type clothespin. If one isavailable, 
it will be a helpful construction guide. 

(ii) Squeezing the handles together will cause the clamp to open and close. 

(iii) The sizes of the components used in this item will vary with the use to be 
made of the holder. The clamp and handle can be reduced in size for use with 
test tubes, or enlarged for use with large flasks. 

(iv) For a simpler version of this design, three or four strong rubber bands 
provide the spring action. Cut the handles and attach the clamps as described. 
Then place the two handles together as indicated in the diagram. Wrap the rubber 
bands around the top part of the handles to draw them together. The chief 
problem with using rubber bands is that they will deteriorate and must be replaced 
from time to time. 




Rubber Bands 



A3. Test Tube Holder 



-76- 




(1) CI 



(2) Handle 



amp 



a. Material Required 
Components 
(1) Clamp 



(2) Handle 



b. Construction 



( 1 ) Clamp 



Qu 
2 



Items Required 
Metal Strapping 

Thin Wire (B) 

Wood Block (C) 




Wire (B) 



(2) Handle 




Slit 



ons of 
Nails (D) 



Dimensions 

20 cm long 

Approximately . 1 cm 
thick, 4-5 cm long 

Approximately 

10 cm x 3 cm x 2 cm 



Bend two loops in each piece 
of strapping (A) as shown. Fit 
the smaller loops to the test 
tubes to be used. Wrap a small 
piece of wire (B) around the 
two pieces of strapping at the 
point where they curve inward, 
just behind the front loops, to 
hold the pieces together. 

Cut a slit about halfway down 
the center of the block (C) . 
Insert the flat portions of the 
strapping clamps into the slit. 
Secure the clamp to the handle 
with two nails . 



c, Notes 

(i) To open this clamp, squeeze together the large loop between the handle and 
the wire. Release the loop to close the clamp. 

(ii) This design is best suited for small, light-weight test tubes. 

(iii) A quick and convenient holder for handling hot test tubes can be made with 
a piece of paper measuring approximately 15 cm x 8 cm. The paper is folded into 



-77- 




thirds, lengthwise, to form 
a strip. This strip can be 
wrapped around a test tube 
near the top. then grasped 
tightly, next to the test tube. 



A4 . Wooden Pinch Clamp 




(2) Fulcrum 



(3) Band 



1) Handles 



a. Materials Required 
Components 

(1) Handles 

(2) Fulcrum 

(3) Band 

b. Construction 

(1) Handles 



(2) Fulcrum 



Qu Items Required 

2 Wooden Strips (A) 

1 Metal Staple or Tack (B) 

2 Rubber Bands (C) 




Staple (B) 



Dimensions 

2 cm x 8 cm x 0.5 cm 

1 cm wide 

0.5 cm x 9 cm 



Sand any splinters or rough 
edges from the wood strips (A) 

Drive the staple (B) or tack 
into the middle of one of the 
handles. Allow about 0.5 cm 
of the staple or tack to 
protrude from the wood. 



(3) Band 



Place the handles together 
with the fulcrum between them. 
Wrap the two rubber bands (C) 
tightly around the handles at 
a point just in front of the 
fulcrum. 



C. Notes 



(i) If the rubber bands are sufficiently tight, it should be possible to 



-79- 




completely close off the flow 

of a liquid such as water through 

1 cm wide rubber tubing, 



(ii) To completely close off plastic tubing and heavier rubber tubing, it will 

be necessary to bend the 
tubing back upon itself and 
secure the clamp at the bend. 




(iii) If pinch-typeclothespinsare available, they may be substituted for this 
clamp. However, it will be necessary to bend rubber tubing as well as plastic 
tubing back upon itself, as in the above illustration, in order to completely 
close the tubing with a clothespin clamp. 



-80- 



A5 . Wooden Screw Clamp 




(2) Bolt Assemb ly 



(1) Jaws 



a. Materials Required 
Components 

(1) Jaws 

(2) Bolt Assembly 



b. Construction 



(1) Jaws 



(2) Bolt Assembly 



Qu Items Required 

2 Wood (A) 

1 Bolt (B) 

1 Wing Nut (C) 



Dimensions 

3.5 cm x 3.5 cm x 
0.7 cm 

. 5 cm diameter, 
approximately 4-5 cm 
long 

To fit bolt (B) 



Sand the wood squares (A) 
to remove rough edges and 
splinters. Drill a hole 
0.6 cm in diameter in the 
center of each square. 

Insert the bolt (B) through 
the hole in each square and 
check to see that the holes 
are just large enough to 
permit the bolt to slide 
through easily . Screw the 
wing nut (C) in place on 
the bolt. 



c .Notes 

(i) To use this clamp with rubber tubing, a short (approximately 4 cm long) 
section of tubing of the same type as that in use is cut. The tubing in use is 




passed through the jaws on one 
side, as close to the bolt as 
possible. The short section 
of tubing is passed through 
the jaws on the opposite side 
to balance the force of the 
clamp. By turning the wing nut 
to tighten the clamp, the flow 
of a liguid or gas through 
rubber tubing can be controlled 
or shut off completely. 

(ii) The flow rate of a liguid or gas through plastic tubing can be controlled 
in the same way, but the stiffness of p lastic tubing makes it difficult to close 

the tubing completely. To close 
plastic tubing, it is necessary 
to bend the tubing back on 
itself, passing each section 
of the tubing through the clamp 
and tightening the wing nut 
as much as possible. 




B. SUPPORTS AND STANDS 



Bl. Wire Gauze 



LH L 


jjjnL 




































1 U u 



(1) Wire 
Gauze 



a. Materials Required 
Components 
(l)Wire Gauze 



b, Construction 
(1) Wire Gauze 



c. Notes 



Qu 

1 



Items Required 
Wire Mesh (A) 



Dimensions 

Approximately 10 cm x 
10 cm of heavy guage 
wire 



Cut the wire mesh (A) to a 

size approximately 10 cm x 10 cm. 

Trim off sharp ends. 



(i) This item is generally used in conjunction with the tripods and ring stand 
described in the sections that follow. The wire screen is placed on the tripod, 
heating stand, or ring to support a flask or beaker. A burner may be placed 
beneath the stand to heat the contents of the container. 



B2. Heating Shelf 



-«^-~ r^OOOO 

^*^ °o oooooo^o 
/^^oo o0 o oo ooo o 

' o^o°ooo o o o o->°Jo ^> 

<g?oW°nOOp0 C 

oo 



O O 0g oO oO" oOj Ogo y 

ooo" og o0^ o5> o / 
O ?^goo0 p0 o / 



(1) Shelf 



a. Materials Required 
Components 
(1) Shelf 



Qu 

: 



Items Required 

Tin Can Top or Bottom (A) 



Dimensions 

10 cm diameter or 
larqer 



b. Construction 
(1) Shelf 



Remove the top (A) or bottom 
from a tin can. Punch many 
holes in it with a larqe 
nail. 



c. Notes 

(i) This item is used in the same way as the wire qauze (IV/B1); that is, to 
support a flask, beaker, or other container upon a tripod or similar support. 



(ii) This is also a useful item to keep hot glass from contactinq the tabletop. 



-84- 



B3. (1) Tripod (Tin Can) 



(1) Tin Can 
Tripod 




a. Material Required 
Components 



Qu Items Required 



(1) Tin Can Tripod 1 Tin Can (A) 



b. Construction 



(1) Tin Can Tripod 




Dimensions 

Approximately 8 cm 
diameter, 12 cm high 



Cut a circle about 5 cm 
diameter from the bottom of the 
can (A) . Mark the position for 
three legs, evenly spaced 
around the can. Allow a ring 
of about 1.5 cm at the top of 
the tripod before marking the 
legs. Allow approximately 
2.5 cm for the width of each 
leg. Then cut along the marked 
lines to produce the three legs. 
With pliers, bend in the outside 
edge of each leg slightly to 
provide extra support . 



C.Notes 

(i) This tripod is simple to make, but it must be used with caution because of 
sharp edges and instability. It is suitable for supporting lightweight items, 
such as a funnel. 



B3 (2) . Tripod (Strappings) 



-86- 




Top 



(2) Legs 



a. Materials Required 
Components 

(1) Top 

(2) Legs 

b. Construction 

(1) Top 



(2) Legs 



q u Items Required 

i Metal Strapping (A) 

3 Metal Strapping (B) 



Dimensions 
1.5 cm x 42 cm 

1.5 cm x 34 cm 

Bend the section of strapping (A) 
into a circle and secure the 
ends with a metal rivet. 

Fold each of the three sections 
of strapping (B) in half and 
pinch the fold closed. Secure 
the open ends of each leg to 
the top with metal rivets. 

c. Notes 

(i) The dimensions given produce a tripod that is useful for most applications, 
but this tripod can also be made larger or smaller by varying the length of the 
strapping used. 



B3 (3) . Tripod (Wire) 




1) Wire Tripod 



a. Materials Required 
Components 

(1) Wire Tripod 

b. Construction 

(1) Wire Tripod 



C .Notes 



Qu I tems Required 
3 Heavy Wire 



Dimensions 

. 2 cm diameter, 
40 cm long 



Twist together the ends of two 
pieces of wire (A) for 
approximately 15 cm to form 
one leg. Twist the free ends 
of these two pieces together 
with each end of the third 
piece of wire. Make each 
twisted leg 15 cm long. Bend 
the legs down to form a tripod 
with a level top, as illustrated. 



(1) This size tripod is useful for most applications, but it may also be made 
larger or smaller by varying the length of the wire used. 



B4 . Collapsible Heating Stand 




(2) Frame 



(1) Legs 



a. Materials Required 
Components 

(1) Legs 

(2) Frame 



Qu I tems Required 
2 Thick Wire (A) 

2 Metal Sheeting (B) 

2 Metal Strapping (C) 



Dimensions 

0.4 cm diameter, 
45 cm long 

10 cm x 3 cm 

1.5 cm x 1 6 cm 



b. Construction 



(1) Legs 



Bend the two pieces of heavy 
wire (A) to the shape indicated. 




(2) Fi 



Roll each of the rectangular 
pieces of metal sheeting (B) 
into long tubes that just fit 
around the legs . 



€ 



c. Notes 



D 




Strapping 



Roll 3 cm at each end of the 
metal strapping pieces (C) 
around each end of the tubes. 

Insert the free ends of the 
legs (A) into the ends of 
the tubing (B) to complete 
this stand. 



(i) Like the tripods, this stand is generally used with wire gauze (IV/B1) 
or heating shelf (IV/B2) . 



(ii) When this stand is not in use, the legs may be removed for ease in storing. 



-90- 



B5 . Ring and Burette Stand with Attachments* 




-* -(1) Ring and Burette 

Stand 




* Adapted from C. S. Rao (Editor), Science Teachers' Handbook, (Hyderabad, India: 
American Peace Corps, 1968), pp 144-' TW. 



-91- 



(2) Burette Clamp 





(4) Ring 



(5) Support Block 



a. Materials Required 








Components 


Qu 


Items 


Required 


Ring and 
(i) Burette Stand 


1 


Wood 


Block (A) 




4 


Wood 


Block (B) 




1 


Wood 


Block (C) 



Dimensions 

14 cm x 18 cm x 2 cm 

2 cm x 4 cm x 1 . 5 cm 

3 cm x 2 cm x 40 cm 



-92- 



(2) Burette Clamp 



(3) Large Clamp 



1 Metal Strapping (D) 

2 Metal Strapping (E) 
- Heavy Wire (F) 

1 Metal Strapping (G) 

2 Metal Strapping (H) 
1 Heavy Wire ( I ) 



(4) Ring 



(5) Support Block 



b. Construction 



1 


Metal Strapping (J) 


2 


Metal Strapping (K) 


1 


Heavy Wire (L) 


: 


Wood Block (M) 




Nails (N) 



(1) Ring and Burette Stand 



Foot 




Base (A) 



1 . 5 cm x 27 cm 

1.5 cm x 5 cm 

0.2 cm diameter, 
10-12 cm long 

1.5 cm x 35 cm 

1.5 cm x 5 cm 

. 2 cm diameter, 
10-12 cm long 

1.5 cm x 50-60 cm 

1.5 cm x 5 cm 

0.2 cm diameter, 
10 cm long 

5cmx2cmx4cm 

0.35 cm diameter, 
8 cm long 



Sand all the wood blocks to 
remove splinters and rough 
edges. Nail a small wood 
block (B) to each corner of 
the flat block (A) to make 
feet . 

In the center of one of the 
short sides of the base (A) 
cut a rectangular notch 3 cm 
long x 2 cm wide. 

Drill 0.6 - 0.7 cm holes at 
1 cm intervals all the way 
through the long block (C) 
as shown. 



-93- 



R\ 




(2) Burette Clamp 

Stand Attachment 





Tightening 

Clip (E) 




Tightening 
Clip (E) 



Adjustment Pin (F) 



\- 



1.0 



Fit this block into the 
rectangular notch in the base 
(A) and nail it in place to 
form the upright. 



Bend the piece of metal 
strapping (D) as shown. Adjust 
the stand attachment section 
so that it will fit securely 
around the upright of the stand, 
yet be able to slide up or 
down along the upright. 

Bend two small pieces of 
strapping (E) as indicated 
to form tightening clips. 
Fit them around the straight 
section of the burette clamp 
to hold the clamp tightly 
closed. 



Bend a 10 - 12 cm piece of heavy 
wire (F) as indicated to make an 
adjustment pin. Adjust the 
width between the legs to match 
the holes drilled in the 
upright . 



-94- 



Stand 
Attachment 




Tightening 
Clip (E) 



Drill a hole approximately 
0.4 cm diameter in the burette 
clamp as shown . 




Burette 
Clamp 



(3) Large Clamp 



Adjustment 
Pin (F) 





To position the burette clamp 
on the stand, slide the 
rectangular section of the 
clamp along the upright to 
the desired height, with the 
clamp facing the base of the 
stand. Align the hole in the 
burette clamp with a hole in 
the upright. Insert one of 
the legs of the adjustment 
pin through the burette clamp 
and into the upright. Insert 
the other leg of the pin into 
the next higher hole of the 
upright . 

Bend the piece of strapping (G) 
in the same general shape as 
the burette clamp, but slightly 
larger. 

Construct two tightening clips 
(H) just as with the burette 
clamp. Position the clips on 
the clamp to hold it closed. 



-95- 



T" 

1.0 



K 



(4) Ring 



Tightening 

Clips (K) 





Construct an adjustment pin 
from a piece of heavy wire (I) . 
Follow the procedure given for 
the burette clamp, 

Drill a hole in the large clamp 
for the adjustment pin, as 
described for the burette clamp. 

Bend the piece of metal 
strapping (J) into the shape 
shown. Bend the ends of the 
strapping into loops approx- 
imately 0.4 cm diameter. 

Make two tightening clips 
according to the directions 
given with the burette clamp 
from the strapping (K) . 
Secure them in the positions 
shown. 

Construct a pin to hold the 
end loops together by bending 
the length of heavy wire (L) 
in half. 

To position the ring on the 
stand, slide the rectangular 
section of the ring along with 
the upright to the desired 
height, with the clamp facing 
the base of the stand. Push 
the pin through the end loops. 



(5) Support Block 
4 

Lb 



s 



"I 



1.0 



Drive two nails (N) all the 
way into a small block of 
wood (M) 1 cm apart. 



Stand 




Position the support block to 
prevent the front of the ring 
from leaning forward under the 
weight of materials placed on 
it. Insert the two prongs of 
the support block into the two 
holes in the upright just 
below the ring. 



Support 
Block 



C.Notes 

(i) To loosen the burette clamp or large clamp, slide the tightening clips 
toward each other. To tighten, slide the clips away from each other. 

(ii) Although the burette clamp and large clamp have adjustment pins to hold 
them in place, they are much more stable when the support block is pushed into 
theupright iammediately beneath the clamp. This prevents the burette clamp or 
large clamp from leaning forward. 

(iii) The ring will safely support masses up to about 1 kilogram. It can 
support round-bottomed containers or flat-bottomed containers with a diameter 
slightly larger than that of the ring. To support smaller containers, a wire 
gauze (IV/B1) or heating shelf (IV/B2) may be placed on the ring. For large 
conatiners, a more stable support, such as one of the tripods (IV/B3) or the 
collapsible heating stand (IV/B4) is recommended. 



B6. Multipurpose Stand 



-97- 



(2) Flask Support 



(3) Test Tube 
Support 




(4) Heating 
Clamp 



(1) Base 



a. Materials Required 
Components 

(1) Base 

(2) Flask Support 



0<i 


Items Required 


1 


Wood (A) 


1 


Heavy Wire 




(coat hanger) (B) 



(3) Test Tube Support 4 



(4) Heating Clamp 



b. Construction 



(1) Base 



Heavy Wire 
(coat hanger) (C) 

Heavy Wire 
(coat hanger) (D) 

Heavy Wire 
(coat hanger) (E) 




Dimensions 

9 cm x 4 cm x 18 cm 

0.2 cm diameter, 
35 cm long 

0.2 cm diameter, 
40 cm long 

0.2 cm diameter, 
15-20 cm long 

0.2 cm diameter, 
20 cm long 



Drill seven holes approximately 
0.2 cm in diameter into the 
wood block (A) as shown. If 
a larger block is used, or if 
more attachments are desired, 
drill more holes, 



(2) Flask Support 




Bend the piece of heavy wire (C) 
as shown to form the base of 
the flask support. Make the 
circular loop about 6 cm in 
diameter. 



Bend the shorter piece of heavy 

wire (B) into a loop to form 

a support for the neck of a 

flask or light-bulb flask (IV/A1), 

Make the open loop about 4 cm 

in diameter. 



Insert the two sections of the 
support into adjacent holes in 
the base. Adjust them so that 
they will support a flask or 
light-bulb flask as illustrated. 



-99- 



(3) Test Tube Support 



Rod or 
Test Tube 




Bend Here 




8-10 



Use pliers to bend each of the 
pieces of heavy wire (D) around 
a wooden rod or test tube of 
the desired diameter (2 cm for 
example) . Follow the steps 
illustrated. 

Insert the supports into holes 
in the base. 



(4) Heating Clamp 




10 - 15 



c. Notes 



Bend the piece of heavy wire (E) 
into loop just as for the test 
tube support shown above. 
However, tilt the loop at an 
angle, rather than vertically 
as was done for the test tube 
supports. Insert the heating 
clamp into one of the holes in 
the base. 



(i) Sizes and number of the supports constructed, as well as the size of the 
base, may be varied to suit individual needs. 

(ii) The heating clamp is used to hold a test tube at an angle while its contents 
are heated. Supporting the test tube at an angle presents a greater area to be 

heated. As a safety measure, 
it allows the mouth of the 
test tube to be pointed away 
from everyone in the vicinity. 




-100- 



B7 . Rack for Light-Bulb Glassware 



(2) Spring 
Clamp 




a. Materials Required 
Components 
(1) Base 



(2) Spring Clamp 
b. Construction 



;i) Base 



q u Items Required 

1 Wood (A) 

1 Wood (B) 

1 Wood (C) 



3 



Metal Strapping (D) 




Top (C) 



Upright (B) 



(1) Base 



Dimensions 

8 cm x 24 cm x 2 cm 

9 cm x 24 cm x 2 cm 
4 cm x 24 cm x 2 cm 

1 cm x 14 cm 



Drill or cut three circular 
holes, 6 cm in diameter in 
the large piece of wood (A) . 
Allow about 1.5cm between 
holes . 

Attach top (C) and upright 
(B) with glue and screws as 
shown, 



Base (A) 



-101- 




Drill a hole approximately 0.5 cm 
diameter in the center of each 
of the pieces of metal strapping 
(D) . Bend each piece of metal 
strapping into the shape shown. 

Center each clamp over each hole 
in the base. Secure each clamp 
to the top (horizontally) piece 
of the base with a screw. 



Notes 



(i) The spring clamp holds the neck of a light-bulb flask securely, while the 
hole in the base supports the round bottom of the flask. 




(ii) This design may be modified to accommodate more flasks, or flasks of 
different sizes. 



-102- 



Stand for Light-Bulb Glassware 




a. Materials Required 
Components 

(1) Flask Stand 

b. Construction 

(1) Flask Stand 



Qu Items Required 
1 Wood Block (A) 



c. Notes 



1) Flask 
Stand 



Dimensions 

9 cm x 9 cm x 4 cm 

Drill or cut a circular hole 
through the center of the block 
(A) . Adjust the diameter of 
the hole to the size of the 
light-bulb flask used: 

6 cm diameter hole for 
bulbs from 60 to 200 
watts. 7 cm diameter 
hole for larger bulbs. 



(i) Another stand for a single piece of light-bulb, or any round-bottomed 
glassware, can be made with a piece of heavy rope approximately 3 cm in diameter. 

The rope is cut to a length 
slightly shorter than the 
maximum circumference of the 
flask, and the ends of the 
rope are taped or spliced 
together to form a ring. 




-103- 



Bamboo Test Tube Rack 



(1) Base 



|Q (2) Test Tube 
Holder 




a. Materials Required 
Components 

(1) Base 

(2) Test Tube Holder 



b. Construction 
(1) Base 



(2) Test Tube Holder 



Qu 

1 



Cut 




Items Required 
Wood Block (A) 

Bamboo Sections (B) 



Dimensions 

1 cmx 7 c m x 1 8 cm 

Approximately 2.5 cm 
outside diameter, 
10 cm long 



Sand the wood block (A) to 
remove splinters and rough 
edges. 

Select bamboo sections (B) 
with thick walls (at least 
0.2 cm). Cut away approximately 
half the length of each bamboo 
section, but leave one upright 
piece as shown. Cement these 
cylinders to the base. 



-104- 



C.Notes 

(i) The upright section remaining on each bamboo cylinder is used to support 
test tubes upside down for drying. 

(ii) The size of the base may be varied to accommodate a convenient number of 
bamboo cylinders . The diameter of the bamboo cylinders may be varied to suit the 
size of the test tubes used. 



-105- 



B10. Wooden Test Tube Rack 



o o o o o o 
o o o o o o 




(1) Test Tube 


Rack 


/ 


s 


a. Materials Required 








Components 




Qu 


Items Required 


(1) Test Tube Rack 




2 


Wood (A) 






2 


Wood (B) 



b. Construction 

(1) Test Tube Rack 



Dimensions 

8 cm x 20 cm x 1 cm 

8 cm x 12 cm x 2 cm 

Drill 12 holes, 2.2 cm in 
diameter at evenly spaced 
intervals in one of the 
larger pieces of wood (A) 
to form the top of the rack. 

Secure the sides (B) to the 
top (A) as shown, with nails 
or cement. Secure the 
bottom (A) in place with 
nails or cement. 



c. Notes 



(i) For larger or smaller test tubes, the dimensions may be varied. 



-106- 



V. GLASSWARE AMD CROCKERY 



A. GLASSWARE 



This section describes the construction of various items of laboratory glassware. 
The chief activity in making these is glass cutting, which is described in detail in 
a separate section. Refer to GLASSWARE TECHNIQUES AND ACCESSORIES (I) for specific 
direction for cutting and working glass. 

B. CROCKERY 

Included in this section is one item composed of concrete. 



-107- 



A. GLASSWARE 



AT. Light Bulb Glassware 




(1) Flask 

or 
Test Tube 




a. Materials Required 

Components 

(1) Flask or Test 
Tube 

b. Construction 

(1) Flask or Test 
Tube 

Sawing 



Qu Item Required 

1 Clear Incandescent 
Light Bulb (A) 




Dimensions 
Varies 



Secure a hacksaw blade in a 
vise. Hold the bulb (A) 
horizontally, and wrapped in 
clcth for safety. Cut around 
the edge of the base near the 
terminals. Remove the end 
thus cut. 



"Adapted from C. S. Rao (Editor), Science Teachers' Handbook , (Hyderabad, India: The 
American Peace Corps, 1968), pp 146^T?7^ 



-108- 



Heat cutting 



Cut Here 




Tape 



With a triangular file, 
puncture the inner seal and 
remove all the parts from 
inside the bulb. Smooth cut 
edge with emery paper or the 
file. 

Wrap a piece of tape around 
the neck of a clear bulb (A), 
about 0.3 cm from the base, as 
a cutting guide. With a 
triangular file or glass cutter, 
make a continuous scratch all 
the way around the neck of the 
bulb. 

Remove the tape, and use the 

electric bottle cutter (I/F2) 

to heat the scratch until the 

bulb cracks all the way around. 

Discard the base and internal 

components. 

Wrap the lower portion of the 
bulb in cloth to protect the 
hands. Hold the cut edge in 
a gas or alcohol burner flame 
until the edge softens and 
curls back upon itself to 
form a smooth lip. 

c. Notes 

(i) The average 150 watt bulb forms a flask of about 150 ml capacity, the 
average 200 watt bulb a flask of about 200 ml capacity 

(ii) Bulbs of 100 watts or less may be used for test tubes. 

(iii) Small test tubes may also be made from glass medicine vials or discarded 
antibiotic ampules, 

(iv) The bulb is made of thin enough glass to be heated safely while containing 
a liquid. 

(v) The glassware made from light bulbs requires special supports to hold it 
upright. Consult the section on Supports, Stands, and Holders (IV) for suggestions. 



-109- 



A2. Beaker 



(1) Beaker 




a. Materials Required 
Component^ 

(1) Beaker 

b. Construction 
(1) Beaker 



Qu Items Required 

1 Wide-bottom Jars or 
Bottles (A) 



Dimensions 
Varies 



Cut off the bottom portion of 
jars or bottles (A) to make 
beakers of various sizes (I/F2), 
Smooth the rough edge by 
filing with emery paper or a 
file. 

c. Notes 

(i) Since bottles and jars are generally made of soft glass, rather than hard, 
heat resistant glass; beakers made from bottles or jars cannot be used for hot 
substances or for substances that are to be heated. When heated, they will break. 



-110- 



A3. Funnel 



(1) Funnel 




a. Materials Required 
Components 
(1) Funnel 


fiu 
1 


Items Required 
Glass Bottle (A) 


Dimensions 
Varies 


b. Construction 









(1) Funnel 



Cut off the top portion of 
narrow-mouthed glass bottles (A) 
to make funnels of various 
sizes (I/F2). 



-in- 



A4. Bell Jar 




\ 




(1) Jug 



a. Materials Required 








Components 


Qu 


Items Required 


Dimensions 


(1) Jug 


1 


Glass Jug or Carboy (A) 


4-8 liters 




1 


Rubber or Cork Stopper (B) 


To fit Jug (A) 


b. Construction 









0) Jug 



Cut off the bottom of the glass 
jug or carboy (A). Sand the cut 
edge smooth with emery paper. 
Seal the neck of the jug with 
the stopper (B). 



-112- 



A5. Watch Glass 




(1) Watch Glass 



a. Materials Required 
Components 

(1) Watch Glass 

b. Construction 
(1) Watch Glass 



Qu Items Required 
1 Light Bulb (A) 




Dimensions 
Varies 

Carefully cut the tops off old 
light bulbs (A) to make watch 
glasses of various sizes. 
Smooth the cut edges by fire 
polishing. 



c. Notes 

(i) The watch glass is commonly used to hold small quantities of a solution fror 
which crystals are to be collected. 



-113- 



A6. Petri Dish 




(1) Petri Dish 



a. Materials Required 
Components 

(1) Petri Dish 

b. Construction 
(1) Petri Dish 



Qu Items Required Dimensions 

1 Wide-bottom Bottles or Varies 

Jars (A) 



Cut off the bottom of a wide- 
bottom glass. bottle or jar (A). 
Make as many as needed. Smooth 
the rouqh edge with emery paper. 



c. Notes 

(i) Jar lids or aluminum foil make satisfactory tops for these dishes. Waxed 
paper or cardboard dipped in wax also make suitable covers. 

(ii) Petri dishes are often used to hold small quantities of a liquid from which 
crystals are to be collected. 

(iii) They may also be used to contain food or culture media for growing bacteria, 
fungi, or molds. When petri dishes are used for culturing purposes, they must be 
used with lids and must be sterilized (BI0L/VII/A2). 



A7. Wash Bottle 



-114- 




(3) Mouthpiece 



(2) Delivery Tube 



(1) Container 



a. 


Materials Required 














Components 


Qu 


Items Required 






Dimensions 




(1) Container 


1 


Glass or Plastic Bottle 


(A) 


Approximately 250 ml 
capacity 






1 


2-Hole Stopper (B) 






To fit container (A) 




(2) Delivery Tube 


1 


Glass Tubing 






Approximately 0.5 cm 
diameter, and at least 
20 cm longer than 
height of container. 




(3) Mouthpiece 


1 


Glass Tubing (D) 






About 0.5 cm diameter, 
and shorter than 
delivery tube. 


b. 


Construction 














(1) Container 






Select 


a glass or plastic bottl 



with a narrow neck and a 
capacity of about 250 ml or 
larger (.A). 

Fit the container (A) with a 
two-hole stopper (B). 






-115- 



(2) Delivery Tube 




(C) 



Make a nozzle (I/D3) at one end 
of the long glass tube (C). Fire 
polish both the nozzle and the 
other end and let the tube cool. 
Next, bend the tube, about 8-10 
cm from the nozzle end at a sharp 
angle as shown. When it is cool, 
carefully push the tube into the 
stopper (B) so that it extends to 
within 0.5 cm of the bottom of 
the container. Trim to the 
correct length, if necessary, 
and fire polish the end. 




Fire polish both ends of the 
glass tube (D). About 8 - 10 cm 
from one end, make a wide-angled 
bend. When the tube has cooled, 
push it carefully into the 
stopper (B). Insert the stopper 
into the container (A). 



-t (C) 



-116- 



c. Notes 

(i) To use the wash bottle, fill it with (distilled) water. Direct the delivery 
tube in the desired direction and blow through the mouthpiece to force water through 
the nozzle in a fine stream. 

(ii) If a soft plastic squeeze bottle is used, only the delivery tube and a one- 
hole stopper are necessary. Squeeze the bottle to force water out the nozzle. 




•117- 



A8. Aspirator 



(3) Outlet 
Tube 



(2) Intake 
Tube 




(1) Container 



(4) Drain Tube 



a. Materials Required 
Components 

(1) Container 

(2) Intake Tube 



(3) Outlet Tube 



Qu Items Required 
Glass Bottle (A) 
2-Hole Rubber Stopper (B) 

Glass Tubing (C) 

Glass Tubing (D) 

Plastic or Rubber Tube (E) 

Screw Clamp or Pinch 
Clamp (F) 

Glass Tube (G) 

Glass Tube (H) 

Plastic or Rubber Tube (I) 



Dimensions 

4-8 liter capacity 

To fit Bottle (A) 

0.5 cm diameter, 
approximately 15 cm long 

0.5 cm x 10 cm 

Approximately 1.0 cm 
diameter, 35 cm long 

(IV/A4 and A5) 



0.5 cm diameter, 10 cm 
longer than height of 
bottle 

0.5 cm x 10 cm 

Approximately 1.0 cm 
diameter, 35 cm long 



-118- 



(4) Drain Tube 



b. Construction 
(1) Container 



(2) Intake Tube 



(3) Outlet Tube 
(E) ( C > 



1 Screw Clamp or Pinch 
Clamp (J) 

1 Plastic or Rubber Tube (K) 

1 Screw Clamp or Pinch 
Clamp (1) 



(IV/A4 or A5) 

Approximately 1.0 cm 
diameter, 20 cm long 

(IV/A4 or A5) 




Fit the bottle (A) with a two- 
hole rubber stopper (B). 
Carefully bore a hole approxi- 
mately 1.0 cm in diameter, 2 cm 
from the bottom of the bottle. 

Make a 90° bend about 5 cm from 
one end of the longer glass tube 
(C). Insert this tube into one 
of the holes in the stopper of 
the bottle. Fit the other end 
of the tube into the plastic or 
rubber tubing (E). Insert the 
short glass tube (D) into the 
open end of the plastic or 
rubber tubing (E). 

Construct a screw clamp or pinch 
clamp (F) (IV/A4 or A5) to close 
the tubing (E). 

Make a 90" bend about 5 cm from 
one end of the longer glass 
tube (G). Insert this tube into 
one of the holes of the rubber 
stopper (B) such that the 
straight section of the tube 
reaches within 2 cm of the bottom 
of the bottle as illustrated. 

Attach the plastic or rubber 
tubing (I) to the other end of 
the glass tube (G). Fit the 
shorter glass tube (H) into the 
free end of the tubing (I) 
and close it with a clamp (J). 



-119- 



(4) Drain Tube 



Insert the plastic or rubber 
tubing (K) into the hole in the 
side of the container extending 
it 1 - 2 cm inside the bottle. 
Seal the tubing (K) in the hole 
with epoxy resin. Close the 
tube with a clamp (L). 

c. Notes 

(i) This item may be used to collect gas by water displacement. First, the bottle 
is filled with water and all three tubes are closed with clamps. The Intake tube is 

then attached to the gas gener- 
From Gas Generator To Drain 

>■ : F=ni , C 



Gas In 



Water ■ 



1C 



Water Out 



±f 



ator and the outlet tube is 
directed into a drain or waste 
receptacle. When both the 
intake and outlet tubes are 
opened (drain tube remains 
closed) gas will enter the 
bottle, and displaced water will 
be forced out through the outlet 
tube. 



Closed 



(ii) The aspirator may also be used to provide suction to aid in filtration. 
Again, the bottle is filled with water, and all three tubes are closed with clamps. 

The intake tube is connected to 



Substance 

xo be 
Fi 1 tered 




Suction-filter 
Flask 



To Drain 
Water Out 



the suction tube of a suction- 
filter flask (VI/A4). The drain 
tube is directed into a drain or 
waste receptacle. The liquid to 
be filtered is poured into the 
filter funnel (fitted with 
filter paper), and the intake and 
drain tubes are opened. The 
outlet tube remains closed. The 
flow of water from the aspirator 
bottle creates a negative 
pressure that tends to increase 
the rate of filtration in the 
suction filtration apparatus. 



-120- 

B. CROCKERY 



Bl. Mortar and Pestle 




,(1) Mortar 



a. Materials Required 
Components 
(1) Mortar 



(2) Pestle 



Qu Items Required 

0.5 kg Sand (A) 

1.5 kg Cement (B) 

1 Tin Can (C) 

0.5 kg Modeling Clay 

(Plasticine) (D) 

Wire Mesh (E) 

Epoxy Glue (F) 

Light Bulb (G) 

Light Bulb (H) 
Epoxy Glue (I) 
Nail (J) 



b. Construction 
(1) Mortar 




Can (C) 



Clay (D) 




(2) Pestle 



Cross Section 



Dimensions 
Fine grain 



Capacity approximately 
0.5 kg 



10 cm x 10 cm 

100 watts 
60 watts 



Approximately 10 cm 
long 



Cut the tin can (C) in half. 
Pack the modeling clay 
(plasticine) (D) into the bottom 
half of the can. Then mold the 
clay into the external shape of 
the mortar. Make the bottom of 
the clay mold smooth and flat, 
as this will be the bottom of 
the mortar. 



-121- 




Wire Mesh (E) 
Concrete (A & B) 
Clay (D) 



Cross Section 



Bulb (G) 




Remove Excess 
Concrete 



Air 
Bubbles 



Make a mixture of 3:1 cement (B)/ 
sand (A) . Add water to make a 
thick concrete paste. Next, 
cover the mold with a 2 - 3 cm 
layer of concrete (A and B). 
Cut the wire mesh (E) into 2 cm 
wide strips and press the strips 
on the coating of concrete. 
Cover the entire surface of 
concrete with the screening 
strips (E). 

Fill the remaining space with 
concrete. Cover the 100 watt 
light bulb (G) with oil and 
press it halfway into the mold. 
Scrape away and discard any 
concrete that overflows the mold. 
Level off the top of the 
concrete. 



Take a thin wooden or metal rod 
and push it in and out of the 
concrete around the bulb (G), 
touching the bulb. Break 
up, in this way, any air bubbles 
between the bulb and the 
concrete. 



Allow at least 24 hours or more 
for the concrete to dry. Then 
cut away the can with a can 
opener and tin snips and peel 



-122- 



(2) Pestle 



Cut 




Bulb 



away the clay mold. Break and 
remove the bulb, taking care to 
remove all pieces of broken 
glass. Place the mortar in a 
large can or crock and cover it 
with water. Allow it to soak 
for three weeks in order to cure. 
Add water to the container as it 
is absorbed by the mortar. 

When the mortar has cured, remove 
it from the water and allow it to 
dry. Then cover the entire 
surface with epoxy glue (F) to 
seal the concrete, fill air 
bubbles, and provide a smooth 
grinding surface. 

Cut the metal tip off the 60 
watt light bulb (H) with a 
hacksaw. Remove the insides. 
File the cut edges smooth with 
a round file. 




Bulb (H) 

Nail (J) 
Concrete (A & B) 



Support the bulb upright in a 
container of sand or appropriate 
stand and fill the entire bulb 
with the concrete paste (A and B). 
Insert a nail almost all the way 
to the bottom of the bulb, to 
provide support for the concrete. 

Allow the concrete to dry (at 
least 24 hours). Break the glass 
glass, leaving the metal end 
intact. Cure the pestle immersed 
in water for three weeks. 
Remove, dry, and coat with epoxy 



-123- 



glue (I), making sure all air 
bubbles are filled. 

c. Notes 

(i) The mortar and pestle are used to grind crystals or lumps of substances into 
powder. The substance to be ground is placed in the mortar, and ground with the 
pestle to the desired consistency. 

(ii) If the epo*y-coated grinding surfaces of the mortar and pestle become worn 
away with use, clean them and reapply a layer of epoxy glue to provide a smooth 
surface. 



-124- 



VI. SEPARATORS AND PURIFIERS 



This section on separators and purifiers has been divided into four subsections: 



A. MECHANICAL SEPARATORS 



These are devices for separating solid/solid, liquid/solid, or solid/liquid 
mixtures. Included are magnets, sieves, filtration apparatus, and separatory funnels. 

B. DISTILLATIONAPPARATUS 



These devices are used for separating liquid solutions and incllde several types 
of distillation apparatus. 

C. ELECTRICAL SEPARATOR 

This device is used in the electrolytic separation of substances and to demonstrate 
Faraday's quantitative laws of electrolysis. 

D. CENTRIFUGAL SEPARATORS 

Centrifugal separators are used to cause the rapid precipitation of materials in 
suspension . 



■125 



A. MECHANICAL SEPARATORS 



Al. Magnets 



N 



S 



(1) Bar Magnet 



a. Materials Required 

Components 
(l)Bar Magnet 

b. Construction 
(1) Bar Magnet 



Qu I tems Required 
1 Bar Magnet 



Dimensions 
PHYS/IX/A1, Notes 

Purchase a magnet, or magnetize 
a steel bar according to the 
instructions described in 
PHYS/IX/A1, Notes. 

c. Notes 

(i) Magnets are used to separate ferromagnetic materials from other materials, 
such as dirt or sand. 

(ii) Magnets in a variety of shapes, materials, and field strength may be 
purchased from commercial sources and may be used in place of the bar magnet above. 



A2 . Cone Sieve 



-126- 




(1! 



Cone Sieve 



a. Materials Required 
Components 
(1) Cone Sieve 



b. Construction 
(1) Cone Sieve 



;;;;; 



Qu I tems Required 
1 Wire Mesh (A) 

1 Thin Wire (B) 



■Cut 

Out 



■■■■■■■■iSiiiiiiiiiii 

■■■■■■■•■•■■■■■■iii*h. 




m 



Dimensions 

Approximately 7 cm x 
7 cm 

Approximately 10 cm 



Cut a circle from the wire mesh 
(A) . Then cut out and remove 
a seqment of the circle as 
shown. 



c. Notes 



Roll the wire mesh into the 
shape of a cone, overlappinq the 
edqes slightly. Thread the 
thin wire (B) in and out of the 
wire mesh, at the overlapped 
edges, to hold them together. 



(i) This cone may be made larger or smaller by varying the dimensions of the 
wire mesh used. 

(ii) Material suitable for replacing the wire mesh may be made by dipping a cloth 
having a very coarse weave into melted wax, varnish, or starch. 

(iii) Sieves are suitable for grading small particles or washing small amounts of 
materials under a stream of water. 



A3. Basket Sieve 



-127- 




(3) Handle 



J 



a. Materials Required 
Components 
(1) Basket 



(2)Fi 



(3) Handle 

b. Construction 
(1) Basket 



Qu I tems Required 
1 Wire Mesh (A) 

4 Thin Wire (B) 

1 Stiff, Heavy Wire (C) 

1 Thin Wire (D) 
1 Wood (E) 




Dimensions 

Approximately 

30 cm x 4 cm 

Approximately 20 cm 

Approximately 4 cm 
diameter, 80 cm long 

Approximately 
80 cm long 

2 cm x 2 cm x 15 cm 



Cut the wire mesh (A) according 
to the pattern shown, and dis- 
card the shaded portions. Then 
fold all the flaps up along the 
dashed lines. Overlap the cut 
edges slightly, and thread the 
thin wires (B) in and out of 
the wire mesh at the overlapped 
edges to hold them together. 



-12E 



(2) Frame 




Bend the heavy wire (C) as shown, 
to fit the dimensions of the 
top of the basket. Allow an 
extension of 8 - 9 cm to fit 
into the handle (E) . 



(3) Handle 




c .Notes 



Fold the top 1 cm of the basket 
around the frame to the inside, 
and lace the thin wire (D) in 
and out of the basket mesh to 
secure the frame in place. 

Drill a hole approximately 0.8 
cm in diameter and approximately 
halfway through the length of 
the wooden handle (E) . 

Insert the straight section of 
the frame into this hole in 
the handle, and cement it in 
place. 



(i) This basket sieve may be made larger or smaller by varying the dimensions 
of the wire mesh, frame, and handle used. 

(ii) This sieve is used just as the funnel sieve in the preceding section, but 
for larger amounts of material. 



-129- 



A4 . Suction-Filter Flask 



(1) Flask 



(2) Funnel 



(3) Suction Tube 




To Aspirator 



a. Materials Required 
Components 
(1) Flask 



(2) Funnel 



(3) Suction Tube 



q u Items Required 

1 Glass Bottle (A) 

1 1-Hole Rubber Stopper (B) 

1 Glass Tube (C) 

1 Funnel (D) 

1 1-Hole Rubber Stopper (E) 

1 Filter Paper (F) 

1 Rubber Tube (G) 



'1 Glass Tube (H) 



Dimensions 

Capacity 250-500 ml 

To fit bottle (A) 

. 5 cm diameter, 
6 cm lonq 

V/A3 

To fit neck of funnel 
(D) 

Approximately 15 cm 
diameter 

1 . cm diameter, 
15 cm lonq 

. 7 cm diameter, 
10 cm lonq 



-130- 



b. Construction 



(1) Flask 




Glass Tube (C) 



CD „ . Hole 



Bore a hole (I/E2) just slightly 
smaller than 1.0 cm in diameter 
in the side of the bottle (A) 
near the top. Insert the glass 
tube (C) into the rubber 
stopper (B) so that approximately 
half the tube protrudes from 
the top of the stopper. Fit 
the stopper into the mouth of 
the bottle. 



(2) Funnel 




Stoppers (B,E) With 
Glass Tube (C) 
Between Them 



Insert the protruding end of 
the glass tube into the stopper 
(E) for the funnel (D) . Push 
the two stoppers together, and 
fit the funnel stopper into the 
neck of the funnel (D) . 



(3) Suction Tube 



Insert the rubber tubing (G) 
into the hole in the side of 
the bottle so that about 1 cm 
of tubing is inside the bottle. 
Seal the tubing in place with 
egoxy resin. Insert a short 
piece of glass tubing (H) into 
the open end of the rubber 
tubing. 



-131- 



c. Notes 

(i) A circle of filter paper is folded as illustrated and placed in the funnel. 
The suction tube is then connected to the water-filled aspirator (V/A8) . The 

material to be filtered is 

placed in the filter paper 
the funnel. Water is then i i 
allowed to drain from the 

aspirator. The partial vacuum 
thus formed will draw air from 



6 



) 



Fold 




' Fold 



the flask, and air on the outside will be drawn through the funnel, causing more 
rapid filtration to occur. 

(ii) Filter paper is available from commercial suppliers, but substitutes include 
paper towels, blotting paper, or cotton. 



-132- 



A5 . Separatory Funnel 



(1) Funnel 




(2) Delivery Tube 




a. Materials Required 
Components 
(1) Funnel 



(2) Delivery Tube 



Qu I tems Required 

Glass Bottle (A) 
Rubber Stopper (B) 

1-Hole Rubber Stopper (C) 
Glass Tubing (D) 

Rubber Tubing (E) 

Wooden Pinch Clamp (F) 



Dimensions 

Capacity 250-500 ml 

Approximately 2 cm 
diameter (large end) 

To fit bottle (A) 

. 7 cm diameter, 
15 cm long 

1 cm diameter, 
8 cm long 

IV/A4 



-133- 



b. Construction 
(1) Funnel 




Select a clear glass bottle (A) 
with a tapered, narrow neck. 
Drill a hole in the bottom of 
the bottle and enlarge it suffi- 
ciently to receive the rubber 
stopper (B) . Smooth the rough 
edge with emery paper before 
sealing. 



(2) Delivery Tube 



QZ>< 



5 H J" — 5 — >J 

ZZD (T ) 



t 

Discard 



t 
Nozzle 



t 
Connector 



Heat the glass tubing (D) with 
a burner and draw it out near 
one end and cut as shown to 
leave a 5 cm long nozzle and a 
5 cm long connector. Carefully 
fire polish all cut edges.' 



-134- 




Glass 

Connector 



Rubber 
Tubing (E) 



Fit the glass connector into, 
but not through, the one-hole 
rubber stopper (C) . Insert the 
other end into the rubber 
tubing (E) , and connect the 
rubber tubing to the nozzle. 
Fit the stopper into the neck 
of the bottle. 

Construct a wooden pinch clamp 
(IV/A4) and use it to close the 
rubber tubing. 



Nozzle 



C. Motes 

(i) The separatory funnel is used to separate two liquids that do not mix. With 

the delivery tube closed, the mixture of liquids is poured into the funnel through 
^."0"^ the hole at the top, (bottom of 

bottle) . The funnel is then 
sealed and shaken vigorously 
for several seconds. Then the 
funnel is secured in a ring 
stand (IV/B4) or other appro- 
priate support and allowed to 
rest undisturbed until the 
liquids separate into layers. 
The lower liquid is then drained 
through the delivery tube by 
opening the pinch clamp. In 

order to allow the funnel to drain properly, the stopper must be removed from the 

top. 




-135- 



(ii) A glass bead just slightly larger than the internal diameter of the rubber 

tubing may be used in place of 



Pinch 
Here 



G 



u 



Glass 
Tube 



Glass 
Bead 



Rubber 

Tube 



Glass 
Tube 



the pinch clamp. Push the bead 
into the rubber tubing before 
inserting the glass nozzle. 
The bead will seal the rubber 
tube. To dispense liquid from 
the funnel, squeeze the tube 
between thumb and forefinger 
at the location of the bead. 



Cross Section 



-136- 



B. DISTILLATION APPARATUS 



Bl. Simple Distillation Apparatus 




a. Materials Required 

Components q u 

(1) Distilling Flask 1 



(2) Delivery Tube 



(3) Collecting 
Flask 

b. Construction 

(1) Distilling Flask 



(3) Collecting 
Flask 



Items Reguired 
Flask (A) 

1-Hole Rubber Stopper 

Glass Tubing (C) 

Rubber or Plastic 
Tubing (D) 

Flask or Bottle (E) 



Dimensions 

Capacity approxi- 
mately 200 ml 

To fit flask (A) 

. 7 cm diameter, 
5 cm long 

1 cm diameter, approx- 
imately 60 cm long 

Capacity approxi- 
mately 200 ml 



Fit the light bulb flask (A) or 
other flask with the one-hole 
rubber stopper (B) . 



-137- 



(2) Delivery Tube 




Support the flask in a stand, 
(IV/B4, B5, or B6) . 

Insert a short piece of glass 
tubing (C) into the stopper in 
the flask. Attach the other 
end of the glass tube to a long 
piece of rubber or plastic 
tubing (D) . Insert another 
short piece of glass tubing (C) 
into the other end of the 
rubber or plastic tubing. 



(3) Collecting Flask 



c .Notes 



Place a flask (E) or jar in a 
bowl or pan of cool water and 
lead the free end of the 
delivery tube into the flask. 



(i) A sample of a liguid — impure water, for example — to be distilled is placed 
in the distilling flask, and the stopper is inserted into the flask. The liquid 
is heated until it boils. As the liquid boils, its vapor travels through the 
delivery tube and is cooled enough by air surrounding the tube to condense and 
drip into the collecting flask. The water in the bowl helps cool the condensed 
liquid still more, as it is quite hot when first collected. 

(ii) This simple apparatus is ideal for student participation in simple distil- 
lation operations involving small volumes of liquids. 



B2 . Condenser 



-13E 



3) Condensing Tube 




(2) Water Jacket 



Stand 



a. 


Materials 


Required 








Components 




Qu 


Items Required 




(1) Stand 




2 

1 
2 
2 


Wood (A) 
Wood (B) 
Nails (C) 
Rubber Bands (D) 



(2) Water Jacket 



(3) Condensing 
Tube 



1 Plastic or Glass Bottle (E) 

1 1-Hole Rubber Stopper (F) 

2 Rubber Tubing (G) 

2 Glass Tubing (H) 

1 Glass Tubing (I) 



Dimensions 

1 8 c m x 1 5 cmx 1cm 

2 5 cmxl5 cmxl cm 

3 cm long 

5 cm x 9 cm 

Capacity approximately 
1-2 liters 

To fit bottle (E) 

1 cm diameter, 
3 cm long 

0.7 cm diameter 
10 cm long 

. 7 cm diameter, 
10 cm longer than 
bottle 



-139- 



c. Construction 



(1) Stand 





Nail (C) 




Trace around the base of the 
bottle (E) on the larger piece 
of wood (B) as shown. Cut along 
the traced line . 



In a similar fashion, make a 
small semicircular cutout to 
accommodate the neck of the 
bottle (E) in one of the 
smaller pieces of wood (A) . 

Nail the two sections with 
cutouts to the third (A) to 
form the stand. Drive a nail 
(C) into each upright to 
anchor the rubber bands (D) 
that hold the water jacket in 
place. 



(2) Water Jacket 



Outlet 




© 



1P^ 




Take a plastic bottle (E) if 
possible, a glass bottle if 
necessary. Drill three holes 
approximately 1 cm in diameter 
in the bottle as illustrated. 



nlet 



-140- 




Glass 
Tube (H) 



Rubber 
Tube (G) 



(3) Condensing Tube 



Fit each short piece of glass 
tubing (H) into a piece of 
rubber tubing (G) . Insert each 
piece of rubber tubing into one 
of the holes in the side of the 
bottle. Seal with epoxy resin 
if necessary to make sure that 
the seal is watertight. 

Fit the mouth of the bottle 
with a one-hole rubber stopper 
(F). 

Insert a long glass tube (I) 
through the hole in the base of 
the bottle, all the way through 
the bottle, and through the 
rubber stopper to the outside 
again. 

Rest the bottle in the stand 
with the base higher than the 
neck and the inlet tube below 
the outlet tube. Loop the 
rubber bands (D) around the 
base and neck of the bottle to 
secure it in position. 



C .Notes 

(i) To use this condenser, fasten a rubber or plastic tube from the flask in 
which a liquid is being boiled to the upper end of the condensing tube (that end 
protruding from the bottom of the bottle) . Another tube, from a cold water source, 
is connected to the inlet (lower) tube, and a third rubber or plastic tube is 
attached to the outlet and led to a drain. As hot gas flows through the con- 
densing tube, it is cooled by the water jacket and condenses, to drip as a liquid 
from the lower end of the condensing tube where it can be collected in a beaker. 



-141- 



B3. Water Still 



(j) Condensing 

?ipe 




(2) Water Jacket 
(Cutaway view) 



(1) Frame Support 



a. Materials Required 
Components 
(1) F rame Support 



(2) Water Jacket 



(3) Condensing 



Qu Items Required 

4 Wood (A) 

1 Wood (B) 

2 Metal Strapping (C) 

1 Large Tin Can (D) 

2 Rubber Tubing (Ej 
2 Glass Tubing (F) 

er Pipe (G) 



1-Hole Rubber Stopper (H) 



D imensions 

4 cm x 5 cm x 25 cm 

2 cm x 16 cm x 25 cm 

1 . 5 cm x 2 3 cm 

Capacity approximately 

1-1.5 kg 

! cm diameter, 

5 cm long 

. 7 C'Fl di amet er 
5 cm long 

1 will JU Lj i -wi'- ■-. : :-xi.iv. ^^ , j 

5 c;;i longer than can 
height 

Approximately 2.5 cm 
diameter (large end) 



-142- 



1 Glass Tubing (I) 



b. Construction 



(1) Frame Support 





wood (A) 



ase (B) 



. 7 cm diameter, 
5 cm long 



Nail two pieces of wood (A) to 
a flat piece (B) to form a base 
and uprights. Then nail two 
more pieces of wood (A) to the 
outsides of the uprights, as 
shown, to form supports for 
the can. 



(2) Water Jacket 




Outlet 



•0 




0-— Inlet 



2.0 
(Diameter) 



Cut a hole approximately 2 cm 
in diameter in the center of 
the bottom of the can (D) . 
Crimp the cut edges inward. 
Cut a smaller hole, not quite 
lcm in diameter, in the side 
of the can near the bottom, to 
accommodate the inlet tube. 
Cut another small hole, not 
quite 1 cm in diameter, in the 
side of the can near the top, 
for the outlet tube. 



-143- 




Watertight Seal 



Glass 
Tube (F) 



Rubber 
Tubing (E) 



Insert each short piece of glass 
tubing (F) into a short piece of 
rubber tubing (E) . Insert each 
rubber tube into one of the two 
small holes in the can. If the 
rubber tubes do not fit snugly 
by themselves, make a water- 
tight seal with candle wax or 
epoxy resin . 




Set the can in place in the 
frame support. To secure it in 
position, nail two pieces of 
strapping (C) to the frame 
support, one on each side of 
the can. 



(3) Condensing Pipe 



Choose a one-hole rubber 
stopper (H) that tightly seals 
the hole in the bottom of the 
water jacket can. Insert a 
short piece of glass tubing (I) 
part way through the stopper, 
from the large end. Insert the 
copper pipe (G) into the 
stopper from the other end. 



-144- 




Copper Pipe (G) 



Insert the condensing pipe into 
the water jacket can through 
the hole in the bottom of the 
can. Push the stopper tightly 
into the hole from the outside. 
Seal with candle wax or epoxy 
resin, if necessary, to produce 
a watertight seam. 



Glass Delivery 
Tube (I) 



c. Notes 

(i) A plastic or rubber tube from a water source is attached to the inlet tube, 
and another tube is attached to the outlet tube and led to a drain. A plastic or 
rubber tube from the container in which water is boiled is connected to the free 
end of the copper condensing pipe. Water vapor flowing through this tube will 
condense and drip from the glass delivery tube at the bottom of the still, where 
it can be collected. 

(ii) This still is suitable for continuous operation, in order to produce dis- 
tilled water for class use. In such a case, a large kettle should be used for 
boiling the water, and a plastic or rubber tube can be attached to the delivery 
tube and led to a storage container. 

(iii) The size of the frame support for this still is determined by the size of 
the can used for the water jacket. Its dimensions will vary, according to the 
size of the can used. 



-145- 



C. ELECTRIC SEPARATOR 



CI. Electrolysis Apparatus 




(3) Collecting 
Tubes 



-s — (4) Frame 

Support 



(2) Electrodes 



ontainer 



a. Materials Required 
Components 

(1) Container 

(2) Electrodes 



(3) Collecting Tube 



(4) Frame Support 



b. Construction 
(1) Container 



Qu I tems Required 

1 Glass Jar (A) 

2 Stiff Wire, Insulated (B) 

2 Thin Copper Sheet (C) 

2 Masking or Adhesive Tape (D) 

2 Test Tubes or Vials (E) 

2 Wood Strips (F) 

2 Wood Blocks (G) 

2 Rubber Bands (H) 



Dimensions 

Approximately 100-200 
ml capacity 

Approximately . 1 cm 
diameter, 25 cm long 

1.5 cm x 3.0 cm 

2 cm x 4 cm 

Approximately 1 . 5 cm 
diameter, 10 cm long 

. 2 cm x 2 cm x 15 cm 

Approximately 2 cm x 
2 cm x 1.3 cm 

Approximately . 2 cm 
x 4 cm 



Choose a small glass jar (A) 
with a capacity of 100 - 200 ml, 
or cut off the top of a jar to 



-146- 



(2) Electrodes 



Solder Here 



make a container of appropriate 
size . 

Strip about 1.5 cm of the insula- 
tion off each end of the stiff, 
insulated wire (B) . Solder one 
end of each wire to a piece of 
the copper sheet (C) , as shown. 




When the solder has cooled, 
roll the copper sheet (C) into 
a spiral plate. 



f% 






^ 



Bend each of the stiff wires (B) 
as illustrated. Make the large 
loop long enough to fit over the 
lip of the container (A) when 
the flat 2 cm portion of the 
wire is resting on the bottom of 
the container . 




Place the electrodes at opposite 
sides of the container. Adjust 
the bends, if necessary, so that 
the plates of the electrodes are 
about 1 cm apart . Secure the 
wires to the outside of the 
container with tape. 



-147- 



(3) Collecting Tubes 



^ 



(4) Frame Support 



slightly 
Tdiameter 

Glue the 



r 



Glue 




narrower than t , 
of the col lee 

two blocks tc 



For the collecting tubes (E), 
use small glass or plastic test 
tubes or vials that are slightly 
taller than the height of the 
container (A) . 

For the frame support, use two 
thin, flexible wooden strips (F) 
about twice as long as the 
diameter of the container. Cut 
two small wooden blocks (G) just 
h e 

diameter of the collecting tubes. 

to one of 
the strips, about 5 cm apart. 



s 



^CT 



Glue 



X 



^TT-n 



Glue the other strip to only 
one of the blocks, as shown. 



c. Notes 



Hold the rubber bands (H) aside 
until the apparatus has been 
set up [see Note (i) ] . 



(i) This apparatus is used to separate water into oxygen and hydrogen, which 
are collected in the tubes. The container is filled with water sufficient to cover 
the terminals by less than 1 cm. A little vinegar or washing soda (Na2C0o • IOH2O) 
is added to the water to increase its conductivity. The collecting tubes are 
filled with the same acidic (vinegar) or basic (Na2C03> solution. Then, with the 
open end sealed with a thumb or forefinger, each tube is inverted and placed into 
the container. The open end of the tube must be placed below the surface of the 
solution before it is uncovered. Then, without being lifted out of the solution, 
each tube is placed over one of the electrodes. 

The frame support may be placed around the two collecting tubes. It is 
secured tightly around the tubes with rubber bands at each end. With the tubes 



-148- 



thus supported, the frame is rested on the top of the container and the tubes are 
carefully adjusted so that the open ends do not rest on the bottom of the container, 
but are about 1 cm above the bottom and below the surface of the solution in the 
container . 

When the free ends of the electrodes are connected to three or more 1.5 volt 
cells connected in series, sufficient current passes through the solution to break 
down the water. Hydrogen is the gas generated at the negative plate (cathode) and 
collected in the tube placed over that plate. Oxygen is generated at the positive 
plate (anode) and is collected approximately one half as rapidly as hydrogen. 

(ii) This apparatus is guite suitable for student use in the laboratory, as it is 
simple to set up and requires little current. With three or more 1.5 volt cells, 
the gases are evolved rapidly and the tubes can be filled in about 20 - 30 minutes. 

(iii) Several factors enhance the efficient operation of this apparatus. The 
small volume of solution used and the proximity of the plates reduce the amount of 
resistance in the system and allow it to function on low current. If the plates 
are cleaned after each use, the apparatus will also function more efficiently. 



-149- 



). CENTRIFUGAL SEPARATORS 



Dl, Hand Drill Centrifuge 



(1) Horizontal Bar 




(2) Test Tube 
Holder 



'(3) Shaft 



a. Materials Required 

Components Qu I tems Required 

(1) Horizontal Bar 1 Wood (A) 



(2) Test Tube 
Holder 



(3) Shaft 



Stiff Wire (B) 



1 Nail (C) 



1 Bolt (D) 



b. Construction 

(1) Horizontal Bar 




Dimensions 

2 cm x 2 cm x 32 cm 

Approximately . 2 cm 
diameter, 30 cm long 

. 5 cm diameter, 
18 cm long 

Approximately . 5 cm 
diameter, 2 cm long 



Drill holes, approximately 0.4 
cm in diameter, at each end of 
the wooden bar (A) . Drill a 
hole through the center of the 
bar, as shown. Make the dia- 
meter of this hole slightly 
smaller than the diameter of 
the nail (C) used for the shaft. 



-150- 




Then, drill a hole perpendicular 
to and intersecting the hole in 
the center of the bar. Make the 
diameter of this hole slightly 

smaller than the diameter of 
the bolt (D) used to hold the 
shaft in place. 



(2) Test Tube Holder 




Take a test tube of the size that 
will be used in the centrifuge. 
Wind one piece of heavy, stiff 
wire (B) (coat hanger wire, for 
example) around the test tube 
two or three times. Make the 
coil very snug around the test 
tube so that the test tube lip 
will not slip through it. Leave 
a straight portion of about 
8 - 9 cm at the top of the coil. 




Bend the straight portion of 
the wire at an angle to the 
rest of the coil as shown. 
About 3 cm from the coil, bend 
the wire again, at right angles 
to the upright portion. 



-151- 




Fit the free end of the wire 
into one of the end holes in 
the horizontal bar. Check to 
see that the fit is loose 
enough for the holder to swing 
easily. Then bend the excess 
wire down, as shown, to secure 
the holder in the horizontal 
bar. 

Repeat this procedure for the 
construction of the second test 
tube holder. 



(3) Shaft 




© 



fc 




Carefully thread the short bolt 
(D) into the center, horizontal 
hole in the horizontal bar. 
Then unscrew it halfway. Fill 
the nail hole (vertical hole) 
with epoxy glue and tap the 
nail (C) into the hole. Tighten 
the bolt against the nail and 
coat the threads of the bolt 
with epoxy glue . 



t>J 



c . Notes 

(i) A precipitate formed by a chemical reaction in a test tube will eventually 

settle to the bottom because of the force of gravity acting upon it. The time 

required for a given precipi- 
tate to settle is dependent on 
several factors; among these 
are the volume, density, and 
particle size of the precipi- 
tate. Spinning such material in 
a test tube in a centrifuge 
reduces this duration by creat- 
ing a strong centrifugal force, 
which causes the heavier 

precipitate to settle to the 
Precipitate 




-152- 



outside of the centrifuge. When the test tube holders are free to pivot outward, 
as in this centrifuge, the test tubes will assume a nearly horizontal position 
when the centrifuge is in rapid motion. Thus, the bottom of the test tube 
becomes the "outside" of the centrifuge, and precipitate is pulled to the bottom of 
the tube. 

(ii) To use this centrifuge, place an appropriately sized test tube containing 
material to be centrifuged through one of the wire holders. To balance the centri- 
fuge, place a test tube with an equal volume of water in the other holder. Take 
care to insure that the test tubes are securely held in place by the holders. 
Seal both test tubes with corks or stoppers to prevent spillage. Fix the end of 
the shaft firmly in a hand drill. Clamp the drill handle tightly in a heavy vise, 
stand at arm's length from the drill, and turn the handle of the drill. The centri- 
fuge will spin, causing the precipitate to collect at the bottom of the test tube. 
To stop the centrifuge, let go of the drill handle and allow the centrifuge to 
continue to spin until it comes to a gentle stop. Another way to stop the centri- 
fuge is to turn the drill handle more and more slowly until it is brought to a 
gentle stop. Sudden stops, which will shake up the precipitate, are to be avoided. 

(iii) If a vise is not available, the drill may be held at arm's length from the 
body while the centrifuge is spun. 

(iv) This centrifuge is capable of being spun at 300 - 500 revolutions per 
minute. It was tested with several precipitates, such as CaC03 and AgN03, and was 
found to reduce settling time from several hours (gravity) to less than one minute. 

(v) This centrifuge, whether clamped in a drill or held at arm's length, must 
be used with extreme care since the test tubes swing close to the user. A safer, 
more permanent centrifuge, which incorporates this centrifuge as its rotating 
assembly, is described in the following section. 



•153- 



D2 . Centrifuge 




a. Materials Required 
Components 
(1) Base 



Qu I tems Required 

1 Wood (A) 
3 Wood (B) 

2 Wood (C) 



Dimensions 

4 cm x 9 cm x 30 cm 

2 cm x 5 cm x 30 cm 

2 cm x 5 cm x 25 cm 



-154- 



(2) Wheel 



(3) Axle 



(4) Head 



1 Wood (D) 

1 Wood (E) 

1 Wooden Spool (F) 

2 Washers (G) 

1 Screw (H) 

1 Screw (I) 

1 Rubber Strip (J) 

1 Wood (K) 

1 Wooden Spool or Dowel (L) 

3 Finishing Nails (M) 

1 Screw (N) 

2 Washers (0) 

1 Nail (P) 

1 Bolt (Q) 

1 Rubber Strip (R) 

2 Metal Strapping (S) 

1 Wood (T) 

2 Stiff Wire (U) 



Bolt (V) 



Approximately 3 cm x 
3 cm x 1 cm 

1 cm x 15 cm x 15 cm 

Approximately 3 cm x 

3 cm x 3 cm 

Approximately D . 8 cm 
inside diameter, 2.0 
cm outside diameter 

Approximately . 6 cm 
diameter, 6 . cm long 

Approximately 3 cm 
long 

1 cm x 50 cm 

4 cm x 4 cm x 16 cm 

3 cm diameter, 
3.5 cm long 

Approximately 5 cm 
long 

Approximately . 6 cm 
diameter, 6 . cm long 

Approximately . 8 cm 
inside diameter, 1.5 
cm outside diameter 

. 5 cm diameter, 
18 cm long 

Approximately . 5 cm 
diameter, 2 cm long 

3.5 cm x 10 cm 

11 cm x 1 cm 

2 cm x 2 cm x 32 cm 

Approximately . 2 cm 
diameter, 30 cm long 

Approximately . 5 cm 
diameter, 2 cm long 



b. Construction 



(1) Base 




With nails or glue and screws, 
secure the thick piece of wood 
(A) to two pieces of wood (B) 
as shown to form the feet and 
bottom of the base. Drill a 
hole approximately 0.5 cm in 
diameter at each end of the 
feet (B) . 



Wood (B) 



-155- 




Next, nail or glue and screw the 
third piece (B) to the bottom of 
the base, in an upright position 
as shown. Secure the two 
shorter uprights (C) in position 
as shown. Glue the small piece 
of wood (D) to the center of the 
horizontal board. When the glue 
has dried, drill a hole about 
0.5 cm in diameter through the 
small piece of wood (D) and a 
centimeter or so into the base 
(A) . 



(2 ) Wheel 




Inscribe a circle in the thin 
wooden square (E) . Carefully 
cut out the circle. Drill a 
hole, 0.7 cm diameter, through 
the center of the circle. 



Wood (E) 




'Rubber Strip (J) 



Fasten the strip of rubber 
sheeting (J) (e.g., from a tire 
inner tube) to the circumfer- 
Handle (F) ence of the wheel with glue and 
small nails with heads. 

With the shorter screw (I), 
fasten the wooden spool (F) 
loosely to the wheel about 
halfway between the center and 
edge of the wheel. The handle 
must be free to rotate around 
the screw. 



-156- 



Wheel 




(3) Axle 




Nail Hole 



Bolt Hole 




Mount the wheel to the base by 
inserting the long screw (H) 
through a washer (G) , through 
the wheel, then through the 
second washer (G) . The holes in 
the wheel and washers should be 
slightly larger in diameter than 
the screw (H) . Finally, turn 
the screw firmly into the small 
piece of wood (D) on the hori- 
zontal board of the base. Make 
certain that the wheel will 
rotate freely around the screw 
without wobbling. 

For the upper section of the 
axle, use the wooden block (K) 
or dowel. Drill a hole approxi- 
mately 0.4 cm in diameter and 
approximately 5 cm deep into 
the center of one end of the 
block. Then drill a second 
hole, about 2.5 cm from the end, 
at a right angle to and inter- 
secting the first hole. Make 
the hole about 0.4 cm in 
diameter, or just a little 
smaller than the bolt (Q) which 
is to be threaded into it. 

Flatten the end of a large 
nail (P) by hammering it on a 
metal block or anvil. 



-157- 



o 



Nail (P) With 
Head Removed 




Bolt (Q) 



Carefully thread the bolt (Q) 
as far as possible into the 
bolt hole in the axle, then 
unscrew it halfway. Fill the 
nail hole with epoxy glue, and 
tap the nail (P) into the hole. 
Tighten the bolt against the 
nail, then coat its threads 
with epoxy glue. Finally, cut 
the head off the nail. 




For the lower section of the 
axle, use a wooden spool (L) 
from which the thread has been 
removed, or a 3 cm diameter 
dowel. Cut the spool or dowel 
to a height of about 3.5 cm. 
Fasten a strip of rubber sheet 
(R) around the outside, just as 
for the wheel. Enlarge the 
hole in the spool to about 0.7 
cm diameter. 



-15? 




Finishing 
Nail (M) 



Washer (0) 



Fit one washer (0) on the top 
of the spool, aligning the holes 
of spool and washer. Drive 
three small finishing nails (M) 
into the top of the spool, out- 
side the washer. Let approxi- 
mately 3 cm of nails protrude 
from the top of the spool, and 
cut off their heads. 



Base 
Uprights 




Locate the position of the axle 
by setting the spool on the 
horizontal board (A) of the 
base such that the rubber strip 
on the spool presses firmly 
against the rubber strip on the 
wheel. Mark the position of 
the center of the spool, and 
drill a small hole at that 
position. 



Overhead View of Base, Wheel 
and Axle Location 



-159- 




( N ) 



Washer (0) 



Washer (0 



Mount the spool (L) on the 
horizontal board (A) of the 
frame by passing a long screw 
(N) through the washer (0) and 
spool (L) ; then through a second 
washer (0) , and into the hole in 
the base. Turn the screw 
firmly into the horizontal 
board, so that the spool is 
free to rotate. In addition, 
the edge of the wheel must rub 
the edge of the spool firmly 
enough so that when the wheel 
turns, the spool also rotates. 




Strapping 
(S) 



Construct strapping braces for 
the axle as follows: Drill a 
hole 0.8 cm in diameter in the 
center of one of the pieces of 
metal strapping (S) . Nail this 
piece to the two shorter up- 
rights (C) of the base such 
that the hole in the strapping 
is directly over the center of 
the spool on the base below. 
Drill a similar hole near one 
end of the other piece of 
strapping (S), and nail it, as 
shown, to the taller upright of 
the base (B) such that its hole 
is directly over the hole in 
the strapping below it. Trim 
off any excess . 



ro 




© 




Slip the nail end of the upper 
section of the axle through the 
holes in the strapping braces. 
Rest the other end of the upper 
section evenly on the tops of 
the three nails in the spool, 
and then drive the upper section 
into the nails with a hammer so 
that the spool and upper sec- 
tion will form a continuous 
solid piece. However, do not 
drive the upper section so far 
down that its end will hit the 
top of the screw and prevent 
the entire axle from turning. 
If this operation has been done 
correctly, the axle will turn 
when the wheel is rotated. 



Head 



c. Notes 



Prepare the horizontal bar and 
test tube holders according to 
directions given for the Hand 
Drill Centrifuge, VI/D1, using 
the wood (T) and stiff wire (U) 
Secure the nail of the axle to 
the centrifuge head according 
to directions given in VI/D1 
with the bolt (V) . 



(i) The centrifuge should be bolted or clamped to the table top before using. 

(ii) To use this piece of apparatus! the substance to be centrifuged is placed 
in an appropriately sized test tube. A second test tube is filled with an egual 
amount of material to be centrifuged or an equal volume of water. Each test tube 
is placed in one of the holders and checked to see that they will not slip out 
through the holder. Both test tubes are sealed with stoppers. Stand at arm's 



-161- 



length from the centrifuge and turn the wheel, first slowly, then more and more 
rapidly. The tubes will be spun about in a nearly horizontal position. Do not 
try to stop the centrifuge suddenly by holding the wheel stationary; either let go 
of the wheel and allow the centrifuge to come to a gentle stop, or turn the wheel 
more and more slowly until the centrifuge is brought to a gentle stop. 

(iii) Matched pairs of test tube holders of various sizes may be constructed and 
used interchangeably in the same centrifuge head, if desired. 

(iv) When the wheel of this centrifuge is turned rapidly, about 150 turns per 
minute, for example, the centrifuge head spins at nearly 500 revolutions per 
minute . 



-162- 



VII. GAS GENERATORS 

The apparatus used in the production of gases has been placed in two sections, one 
of which contains the complete apparatus for gas generation while the second section 
contains two devices useful in collecting gases. 

A. GAS GENERATORS 



Three types of generators will be given: simple devices for which no special 
equipment is required; and an inexpensive version of Kipp's gas generator. 

B. ACCESSORIES 



Included here are the beehive shelf and metal sheet shelf. 



-163- 



A. GAS GENERATORS 



Al . Simple Gas Generator and Collecting Apparatus 



(1) Generator 



(2) Delivery Tube 




(3) Collecting 
Apparatus 



a. Materials Reguired 
Components 
(1) Generator Tube 



(2) Delivery Tube 



(3) Collecting 
Apparatus 



b. Construction 

(1) Generator Tube 



q u Items Reguired 

Test Tube or Flask (A) 

1-Hole Rubber Stopper (B) 



Glass Tubing (C) 

Rubber or Plastic 
Tubing (D) 

Glass Tubing (E) 



Test Tube, Flask, or 
Bottle (F) 

Bowl or Pan (G) 



Dimensions 

Capacity at least 
50 ml 

To fit generator 
tube (A) 

0.5 cm diameter, 
5-10 cm long 

To fit glass tubing 
(C and E), 30 cm long 

0.5 cm diameter, 
15-25 cm long 

Capacity at least 
50 ml 

250 ml or greater 
capacity 



For the generator tube, use a 
hard-glass test tube or flask 
suitable for heating (A) . 
Secure test tube in a slanted 
position with an appropriate 
clamp or support (IV/B5 or B6) . 



-164- 



(2) Delivery Tube 



(3) Collecting Apparatus 



Fit the generator tube with a 
one-hole rubber stopper (B) . 

Insert the shorter glass tube 
(C) through the one-hole rubber 
stopper. Connect the rubber or 
plastic tubing (D) to the free 
end of the glass tube (C) . 
Bend the longer glass tube (E) 
at a 90' angle or less, and 
connect it to the flexible 
tubing (D) . 

Select a large test tube, 
flask, or bottle (F) . Fill with 
water, cover the opening, and 
invert in a bowl or pan of 
water (G) so that the water is 
held in the bottle (F) . Uncover 
the opening and place the free 
end of glass tubing (E) into the 
mouth of the collecting tube. 

c. Notes 

(i) This apparatus is suitable for student use in generating small amounts of 
gases which are insoluble or only slightly soluble in water. 

(ii) Small amounts of reactants are placed in the generator tube and carefully 
heated (if heating is required) . The gas generated passes through the delivery 
tube, and is collected by displacing the water in the collecting tube. 



A2 . Flask Generator 



-165- 



(1) Generator 

Flask 



(2) Funnel 




) Delivery Tube 



a. Materials Required 
Components 
(1) Generator Flask 



(2) Funnel 



(3) Delivery Tube 



b. Construction 



(1) Generator Flask 



(2) Funnel 



q u Items Required 

1 Flask or Bottle (A) 

1 2-Hole Rubber Stopper (B) 

1 Long-necked Funnel (C) 

2 Glass Tubing (D) 

1 Plastic or Rubber 
Tubing (E) 



Dimensions 

250 ml capacity or 
larger 

To fit flask (A) 

Approximately 10 cm 
diameter (large end) 

0.5 cm diameter, 
15-25 cm long 

To fit glass tubing, 
approximately 30 cm 
long 



(3) Delivery Tube 



Support the flask or bottle (A) , 
if necessary, in a suitable sup- 
port. Fit the flask with a two- 
hole rubber stopper (B) . 

Select a funnel (C) with a 
sufficiently long neck to reach 
nearly to the bottom of the 
flask (A) . Carefully push the 
funnel neck through one of the 
holes in the stopper (B) . 

Make a 90' bend in each piece 
of glass tubing (D) . Connect 



-166- 



these with flexible tub tng (E) 
Insert one of the glass tubes 
into the second hole of the 
rubber stopper (B) . 



c. Notes 



(i) This apparatus is used in conjunction with the collecting apparatus just as 
described in the previous section (VII/A1). 

(ii) This device is generally chosen when the gas generating reaction involves 
a solid (such as zinc) and a liguid (such as dilute sulfuric or hydrochloric acid) . 
The solid is placed in the bottom of the generator flask, then the rest of the 
apparatus is placed in position. When the collecting bottle is in place, the 
liguid reagent is added through the funnel. Thus, the reaction does not begin 
until the apparatus is sealed. Additional liguid can be added to the flask with- 
out dismantling the apparatus. 

(iii) If a funnel made from a cut-down bottle is used (V/A3), it will be necessary 

to adapt the construction of 
this item slightly . Connect 
such a funnel to the flask (A) 
with a long piece of glass 
tubing running through the 
stopper (B) and a one-hole 
stopper fitted into the funnel. 




-167- 



A3 . Kipp ' s Generator * 





(4) Funnel 



3) Gas Delivery 
Tube 



2) Reaction 
Flask 



(1) Acid 
Container 



*Adapted from C S. Rao (Editor), Sci ence Teachers' Handbook, (Hyderabad, India: 

American Peace corps, 1968), pp 174-175. 



-168- 



a. Materials Required 

Components q u 

(1) Acid Container 1 



(2) Reaction Flask 



O) Gas Delivery 
Tube 



(4) Funnel 



Items Required 
Glass Jar (A) 

Rubber Stopper (B) 

Plasticine (Modeling 
Clay) or Pitch (C) 

Glass Bottle (D) 

1 or 2-Hole Rubber 
Stopper (E) 

Glass Tubing (F) 

Rubber Tubing (G) 

1-Hole Rubber Stopper (H) 

Glass Tubing (I) 

Rubber Tubing (J) 

Pinch Clamp (K) 
Glass Bottle (L) 

1-Hole Rubber Stopper (M) 



Dimensions 

Capacity approxi- 
mately 500 ml 

Approximately 2 . cm 
diameter (large end) 

4cmx4cmx4cm 



Capacity approxi- 
mately 500 ml 

To fit bottle (D) 



Approximately . 7 cm 
diameter, 30 cm long 

1 . cm diameter, 
3 cm long 

Approximately 2 . cm 
diameter (large end) 

. 7 cm diameter, 
5 cm long 

1 . cm diameter, 
30 cm long 

(IV/A4) 
Capacity approximately 

1 liter 

To fit bottle (L) 



b. Construction 



(1) Acid Container 



Select a low, wide-mouth jar 
with a capacity of about 500 ml 
(A) . Drill a hole in the side 
of the jar, just above the 
bottom, (I/E2) . Enlarge the 
hole, by filing with a round 
file, to a diameter of 1.7 - 
1.8 cm. Seal this hole with a 
solid rubber stopper (B) . 



-169- 



(2) Reaction Flask 



Stopper (H) 




Bottle (D) 



0.8 - 0.9 
Diameter 



1.7 - 1.8 
Diameter 



For the reaction flask, choose 
a narrow-necked bottle (D) that 
will just fit into the neck of 
the acid container (A) . Drill 
a hole in the center of the 
bottom of the bottle (D) , and 
enlarge the hole to a diameter 
of 0.8 - 0.9 cm. Drill a 
second hole in the side near 
the bottom. Enlarge this hole 
to a diameter of 1.7 - 1.8 cm. 
Fit a one-hole rubber stopper 
(H) into the side hole. 




(E) 



Select a stopper (E) that fits 
the neck of the bottle (D) . If 
it is a one-hole stopper with 
a round file, enlarge the hole 
in the stopper to about two to 
three times its normal diameter. 
Fit this stopper into the neck 

of the bottle. If a two-hole 

stopper is available, make no 
alterations, and fit the 
stopper into the neck of the 
bottle (D) . 



-170- 



o 



M 



"1- 

4 - 5 



U 



Rubber Tubing (G) 



Glass Tubing (F) 



Fire polish (I/D4) both ends of 
the glass tubing (F) . Insert 
one end into the short length 
of rubber tubing (G) . Allow 
4 - 5 cm of glass tubing (F) to 
protrude beyond the rubber 
tubing (G) . 




Insert the long end of the 
glass tubing (F) into the 
bottle (D) , from the bottom. 
Fit the end through the en- 
larged hole of the stopper (E) , 
and carefully push and twist 
until the rubber tubing (G) 
around the glass tightly seals 
the hole in the bottom of the 
bottle (D) . 

Set the reaction flask (D) , 
neck down, into the neck of the 
acid container (A) . Adjust and 
cut the glass tubing (F), if 
necessary, so its lower end is 
about 0.5 cm from the bottom of 
the acid container (A) . 

Roll the modeling clay (plasti- 
cine) (C) into a long cylinder 
and wrap it around the seam 
between reaction flask (D) and 
acid container (A) . Press the 
clay firmly in place to make an 
airtight seal. 



-171- 



(3) Gas Delivery Tube 



(4) Funnel 




^s 



/ 



"\ 



s 



\ 




Bottle (L) 



+ 



Cut 



C. Notes 



Insert a short piece of glass 
tubing (I) into the stopper in 
the side of the reaction flask. 
Attach rubber tubing (J) to the 
other end of the glass tube. 
Use a wooden pinch clamp (K) 

(IV/A4) or other suitable clamp 
to close the rubber tubing. 

Construct a large funnel with a 
capacity equal to that of the 
acid container by cutting off 
the bottom third of a narrow- 
necked bottle (L) (I/F2) . 
Smooth the rough cut edge of 
the funnel with emery cloth. 
Select a one-hole rubber 
stopper (M) to fit the funnel 
neck. Insert the glass tube 
(F) from the reaction flask (D) 
into the stopper (M) . 

Invert the funnel (L) and fit 
its neck tightly over the 
stopper (M) . 

Support the funnel in a ring 
stand (IV/B5)or other suitable 
holder . 



(i) To complete the gas generating apparatus, the gas delivery tube of the 
Kipp's Generator must be connected to a suitable collection device such as that 
described in VII/Al_or the aspirator described in V/A8. 

(ii) The solid reactant, such as zinc chips is added to the reaction flask (D) 
through the hole in the side. The solid will sit, for the most part, on the 
stopper (E) in the neck of the flask. The stopper (H) and gas delivery tube are 
then securely replaced in the reaction flask, and all connections and seals are 
checked to insure that they are gastight. Then the liquid reagent, such as 
6M hydrochloric acid, is poured into the funnel (L) . 

When the pinch clamp (K) is removed from the gas delivery tube, the acid 
will flow into the acid container (A) . As the acid level rises above the neck 



-172- 



of the reaction flask (K) , it will flow into the reaction flask through the 
enlarged or second hole of the stopper (E) and will react with the solid to pro- 
duce a gas (hydrogen, in this example) . The gas will pass through the delivery 
tube to the collecting vessel. 

(iii) The reaction can be stopped without removing any of the reactants or 
dismantling the equipment . When the gas delivery tube is closed with the pinch 
clamp, the pressure of the gas accumulating in the reaction flask will force the 
acid out of the reaction flask and back into the acid container until it is no 
longer in contact with the solid. Some of the acid will also be forced back up 
the glass tube and into the funnel. The funnel must therefore be large enough 
to safely contain a large volume of acid that might be backed up. 

To restart the reaction, the delivery tube is opened, and acid again flows 
into the acid container and. reaction flask to evolve more gas. 

(iv) This device is suitable for evolving large quantities of a gas for class 
use, or as a demonstration. it should be possible to build a larger model, but 
experimentation with the size relationships between the funnel, reaction flask, 
and acid container will be necessary. 

(v) Ifthe Kipp's Generator is to be employed for continuous classroom use, a 

safety tube and funnel may be 




Funnel 



Safety Tube 



Bottle- 
Substitutes for 
Funnel (L) 



Reaction 

Flask (D) 



substituted for the large 
funnel to prevent the escape of 
unpleasant or undesirable acid 
fumes. A piece of glass 
tubing, approximately . 7 cm 
diameter and 35 - 40 cm long, 
is bent as shown. This is 
connected, by means of a 
rubber stopper at the upper 
end, to a funnel. A bottle 
with a hole drilled in the 
bottom is substituted for the 
large funnel (L) , and the lower 
end of the safety tube is 
connected to this bottle with a 
one-hole rubber stopper or short 
piece of rubber tubing. 

The whole apparatus must be 
supported in a stand or frame 
of some kind. 



-173- 



B. ACCESSORIES 



11. Beehive Shelf 




0) Can 



a. Materials Required 
Components 

(1) Can 

b. Construction 

(1) Tin Can Shelf 



Qu I tems Required 
1 Tin Can (A) 



Dimensions 

9 cm diameter x 
5 cm high 



Select a short tin can with 
one end removed (A) . Cut a 
V-shaped notch about 1 cm high 
in the side of the can. Drill 
a hole 1.5 cm in diameter in 
the center of the end of the 
can. Varnish the can. 

c. Notes 

(i) The beehive shelf is placed in the bottom of a pan of water. A gas collect- 
ing tube or jar, filled with water as described in VII/A1, is inverted on the 
shelf, with the mouth of the jar over the hole in the shelf, The gas delivery 

tube is then inserted through 
the notch of the shelf, up 
through the hole, and into the 
neck of the collecting jar. 

From Gas 
Generator 



Beehive 
Shelf 




-174- 



B2 . tfetal Sheet Shelf 




o o o 




Shelf 



a. Materials Required 
Components 

(1) Shelf 

b, Construction 

(1) Metal Sheet Shelf 



Qu I tems Required 
1 Metal Sheet (A) 



Dimensions 

Approximately 0.05 cm 
thick, 8 cm x 30 cm 



Cut the metal sheet from heavy 
aluminum sheeting or a tin can. 
Cut three holes, 1.5 cm in 
diameter, in the sheet (A) as 
shown. Bend the edges up as 
shown. Finally, make curved 
bends approximately 1 cm from 
each end. 



c. Notes 

(i) This shelf may be hung from the sides of a rectangular pan measuring from 
12 to 20 cm wide. The shelf must be covered with water. Collecting bottles, 
filled with water, are inverted over the holes and set on the shelf. 



-175- 



VIII. METALWARE AND CLEANER 



A. METALWARE 

The items in this section are small pieces of metalware which can be constructed 
from scrap strapping, wire and the like. Items which can be improvised from normal 
household items, such as knives, have not been included. 

B. CLEANER 



This item can be used to clean the test tubes utilized in chemistry. 



Al. Flame Test Wire 



-17( 



A . METALWARE 




(1) Wire 



a. Materials Required 
Components 

(1) Wire 

b. Construction 

(1) Wire 



c. Notes 



Qu I tems Required 
1 Transfer Loop 



Dimensions 

BI0L/VII/A3 

SeeBI0L/VII/A3 for construc- 
tion details . 



(i) Use this wire to flame test compounds. Simply get a small amount of the 
chemical caught in the wire loop and hold it in a hot flame to observe the color 
of the flame. 



-177- 



A2 . Deflagrating "Spoon" 




(1) Spoon 



a. Materials Required 
Components 

(1) Spoon 

b. Construction 



Qu I tems Required 

1 Metal Strapping (A) 



Dimensions 



(1) Spoon 



Bend Slightly 




About 10 cm x 3 cm 

Carefully sand off all the 
paint from one end of the 
metal strapping (A) so that 
there is only bare metal. Make 
a slight bend in this end about 
1.0 cm from the end. 



Sand Both Sides 



c . Notes 

(i) To use the deflagrating spoon, place a small amount of the chemical to be 
heated on the bent portion of the strapping. Hold the spoon in a holder (e.g., 
IV/A4 ) . and hold the chemical in the flame of a burner until it burns or melts. 
The deflagrating spoon is used mainly in doing flame tests on unknown compounds. 

(ii) When the end of the spoon becomes contaminated, either clean it with sand- 
paper or simply cut it off, sand the new end, and bend it as before. 



A3. Spatula 



C 



\. 



-17£ 




(1) Spatula 



a. Materials Required 
Components 
(1) Spatula 

b. Construction 
(1) Spatula 



c 



^«w 



Handle 



Notes 



Qu I tems Required 

1 Tin Can or Strapping 

Wire (A) 



=o 



\ 



scoop 



Dimensions 

20.0 cm long, 
3.0 cm wide 



Cut a piece of tin can metal 
(A) or a piece of wire 
strapping to the desired length 

and width. Cut the metal to 
the shape illustrated. 

Make a depression in the scoop 
by hammering a steel ball in 
the circle. 

Depress the center of the 
handle slightly for easier 
handling. 



(i) This spatula may be converted to a deflagrating spoon by bending the 
handle backward at a 90' angle with the shaft and bending the scoop forward at a 
90' angle with the shaft. 



-179- 



B. CLEANER 



Bl. Test Tube Cleaner or Spatula 



c 



;i) Handle 




(2) Cleaner 



a. Materials Required 
Components 

(1) Handle 

(2) Cleaner 

b. Construction 

(1) Handle 



£ 



Qu I tems Required 
1 Wooden Dowel (A) 

1 Piece of Rubber Inner 
Tube (B) 



Dimensions 
25 cm long 

5 c m x 5 c m 



\ 



Use a piece of wooden dowel (A) 
about 2 5 cm in length. Make 
a slit about 2 . cm long in 
the center of one end of the 
handle. 



Slit 



(2) Cleaner 




Cut Along 
This Line 



Cut a triangular piece of 
rubber (B) about 5 . cm long 
from a discarded inner tube. 
Insert this in the slit made 
in the handle. Drive a small 
nail through the handle and 
cleaner to hold them in place, 
if necessary. 



-180- 



IX. HEATERS AND DRYERS 



The apparatus in this section has been divided into two categories, as follows: 

A. DRYERS 

Dryers are devices used to remove the moisture content from chemical compounds. 

B. HEATER 

This is a device that is intended to produce a heat intense enough to incinerate 
precipitates . 



-181- 



A. DRYERS 



Al . Dessicator 



!> 




(3) Tubing 



(2) Dryer 



(1) Container 



a. Materials Required 
Components 
(1) Container 



(2) Dryer 



(3) Tubing 



q u Items Required 
1 Glass Jar (A) 

1 Lid (B) 

1 Small Tin Can (C) 

1 Wire Mesh (D) 

Calcium Chloride or 
Silica Gel (E) 

1 Rubber Tubing (F) 

1 Glass Tube (G) 

1 Screw Clamp or Pinch 
Clamp (H) 



Dimensions 

Capacity 200 ml 
or more 

To fit jar (A) 

To fit inside jar (A) 
To cover tin can (C) 



1 cm diameter, 
15 cm long 

0.7 cm diameter, 
5 cm long 

(IV/A4 or A5) . 



-182- 



b. Construction 
(1) Container 



(2) Dryer 



Glass Tube (G) 




Rubber Tubing (F) 



Select a jar (A) with a screw 
top (B) and a very wide mouth. 
Cut a hole slightly less than 
1.0 cm in diameter in the center 
of the jar lid (B) . 

Take a short tin can (C) which 
fits easily into the jar, or 
cut a taller can to a height 
of 2 - 3 cm. 

Place a drying agent, such as 
calcium chloride (CaCl ? ) 
pellets or silica gel (C) in 
the can. Cover the can with 
wire mesh (D) and set it in 
the bottom of the jar (A) . 

Cut a section of about 3 cm 
from the piece of rubber 
tubing (F) . Insert one end 
of the glass tube (G) all the 
way into this short piece of 
rubber tubing. Insert the 
other end of the glass tube (G) 
into the longer section of 
rubber tubing. Push the 
shorter piece of rubber tubing, 
with the glass tube inside, into 
the hole in the top of the jar 
lid (B) . Seal the tubing into 
the hole in the jar with cement, 
if necessary, to make an 
airtight seam. Seal the long 
rubber tube with a pinch clamp 
(IV/A4) or screw clamp (IV/A5) . 



C. Notes 

(i) Powders or substances to be kept free of moisture are placed in containers 
inside the dessicator, and the top is sealed. The rubber and glass tube arrangement 
permits a partial vacuum to be formed in the dessicator if it is used in 
conjunction with a vacuum pump. 



-183- 



A2, Drying Tower 



Jl) Container 




(2) Tubing 



a. Materials Required 
Components 
(1) Container 



(2) Tubing 



b. Construction 
(1) Container 



g u Items Required 

1 Glass Bottle (A) 

1 1-Hole Stopper (I 
3 Rubber Tubing (C) 

2 Glass Tubing (D) 



Dimensions 

Capacity approximately 
300-400 ml 

To fit bottle (A) 

1 cm diameter, 
5 cm long 

0.7 cm diameter, 
5 cm long 



Drill a hole just slightly 
smaller than 1.0 cm in the side 
of the bottle (A) near the 
bottom (I/E2) . Fit the bottle 
(A) with a one-hole cork or 
rubber stopper (B) . 



-184- 



(2) Tubing Insert one of the pieces of 

glass tubing (D) into the one- 
hole stopper, and push a piece 
of rubber tubing (C) on to the 
other end of the glass tube. 

Insert one piece of rubber 
tubing (C) into the hole in the 
bottle (A) , and cement it in 
place to make an airtight seal. 
Push the second piece of glass 
tubing (D) into the rubber 
tubing (C) , and connect the last 
piece of rubber tubing (C) 
tothe glass tube (D) . 

c . Notes 

(1) This apparatus is used in removing moisture from gases. For example, 

moisture can be eliminated f rom H q n CI-,, an d S0 9 by filling the drying 

Z Z Z Z z 

tower with calcium chloride or other drying agent and connecting it by means 
of the tubing connections at top and bottom, between the gas generator and 
collecting device. As the gas passes through the drying tower, moisture is 
absorbed by the drying agent. 



A3. Electric Lamp Dryer 



-185- 




(2) Lamp 



(1) Support 



a. Materials Requir 


ed 






Components ' 




Qu 


Items Required 


(1) Support 




1 
1 
1 


Wood (A) 
Wood (B) 
Wood (C) 






2 


Wood (D) 



Dimensions 

30 cm x 30 cm x 1 cm 
1 cm x 2 cm x 32 cm 
1 cm x 2 cm x 18 cm 
4 cm x 4 cm x 2 cm 



( 2 ) Lamp 



Lamp Socket (E) 

Insulated Electrical 
Cord and Plug (F) 

Incandescent Bulb (G) 

Large Staples or 
Thin Nails (H) 

Bolt (I) 



1 


Nut (J) 


1 


Wire Mesh (K) 


1 


Thin Wire (L) 


1 


Aluminum Foil 



100 watts 



Approximately 
0.8 cm x 3 cm 

To fit bolt (I) 

20 cm x 2 cm 

15 cm 

20 cm x 2 cm 



-186- 



b. Construction 
(l)Support 




Construct the support as 
illustrated. Use glue and 
screws to secure the parts 
(A) , (B) , (C) and (D) to 
one another . 



(2) Lamp 




Secure the lamp socket (E) to 
the top horizontal bar (C) 
with the nut (J) and bolt ( I ) 



Attach the electrical cord, 
with plug attached (F), to the 
socket (E) . Run the wire along 
the top bar (C) and down the 
back of the vertical support (B) 
Secure the cord in position 
with large staples (H), bent 
nails, or tape. 



-187- 





From the wire mesh (K) , cut a 
circle. Cut out and remove the 
shaded portion as shown. cut 
a similar but slightly larger 
shape from the aluminum foil (M) 
Curve the wire mesh (K) into a 
cone with an open end that will 
fit over the base of the 
incandescent bulb (G) , and 
secure the cut edges together 
by threading the thin wire (L) 
in and out of the wire mesh. 

Cover the inside of the wire 
mesh cone (K) with the foil (M) , 
shiny side to the inside of 
the cone. Secure the foil 
reflector (M) to the wire 
mesh (L) by bending the foil 
edges around the wire mesh cone. 



Notes 



Slip the small end of the 
reflector over the neck of 
the bulb (E) and screw the 
bulb into the socket (E) . 



(i) The light provides a heat source for drying precipitates which are placed 
in shallow containers, watch glasses (V/A5) or petri dishes (V/A6) . 

(ii) Experimentation in the use of the dryer might include varying the size of 
the reflector, distance of the bulb from the material, wattage of bulb and 
number of bulbs used. 



A4. Sand Bath 




(1) Can 



a. Materials Required 
Components 

(1) Can 

b. Construction 
(l)Can 



c. Notes 



Qu Items Required 
1 Larqe Tin Can (A) 
Sand (B) 



Dimensions 

15-20 cm diameter 



Use a larqe, shallow tin 
can (A) as a container, or 
cut a larqer can to a 
heiqht of about 5 cm. Fill 
the container with sand (B) . 



(1) Solutions or precipitates that must be evaporated or dried slowly may be 
placed in shallow containers, watch qlasses, or petri dishes which are rested on 
the sand, The sand bath is then rested on a tripod (IV/B3), heatinq stand (IV/B4) 
or other suitable support and slowly heated with an alcohol or qas burner. 



-189- 



A5. Water or Steam Bath 




;i) Container 



a. Materials Required 
Components 

(l)Container 

b. Construction 

(1) Container 



C. Notes 



Qu Items Required 
1 Tin Can (A) 



Dimensions 

Capacity approximately 
150-300 ml 



Use an empty, clean tin can 
(A) for the container. Fill 
it about 2/3 full of water. 



(i) Use of the water bath is a safe way to heat materials that must not, for 
technical or safety reasons, be heated above about 100'C. Test tubes containing 
material to be heated are placed in the water bath. The water bath is rested on 
asuitable support and heated with an alcohol or gas burner. Materials heated 
in the test tubes will be heated to a temperature not higher than the boiling 
point of the water. 

(ii) The water bath may be converted to a steam bath by the addition of a row 
of holes punched or drilled around the can near the top. The can is filled about 

1/3 full of water, and a 
petri dish (V/A6) or watch 
glass (V/A5) containing 
material to be heated is 
rested on top. 




■190- 



The steam bath is rested on a suitable support and heated; as the water boils, 
the steam will heat the material in the petri dish or watch glass and will be 
able to escape through the holes in the top of the can. 



-191- 



B. HEATER 



Bl. Blowpipe for Charcoal Block 




(I) Blowpipe 



(2) Charcoal Block 



a. Materials Required 
Components 
(1) Blowpipe 



(2) Charcoal Block 

b. Construction 
(1) Blowpipe 



(2) Charcoal Block 



Notes 



Qu 

: 



Items Required 
Rubber Tubing (A) 

Glass Tubing (B) 
Charcoal Block (C) 



Dimensions 

Approximately 1 . cm 
diameter, 10 cm long 

Approximately . 7 cm 
diameter, 20 cm long 



Heat the glass tubing (B) 
near one end and bend it 
slightly as shown. Then 
heat it again, just past 
the bend, in order to draw 
it out to form a nozzle. 

Fit the rubber tubing (A) 
over the other end of the 
glass tube (B) . 

Use a lump of charcoal (C) 
as a heat source. 



(i) This item is used to create a concentrated heat source by blowing through 
the blowpipe onto the charcoal ember. 



-192- 



X. MOLECULAR MODELS 

Four types of models to assist in the instruction and understand 1'ng of molecular 
structure are described. 

A. SPACE-FILLING MODELS 



These roughly represent relative sizes and positions of atoms within a molecule. 

B. SKELETAL MODELS 

These models more accurately represent atomic radii and bond angles than do those 
in the previous section. 

C. CRYSTAL MODELS 



These are three-dimensional models that represent shape and atomic packing within 
crystals . 

D. KINETIC-MOLECULAR MDDEL 



This two-dimensional model demonstrates the kinetic theory of matter. 



Al. Ball-and-Stick Models 



193- 



A. SPACE-FILLING MODELS 




3) Flexible 
Connector 



C 2 H 2 



a. Materials Required 
Components 
(1) Ball 



g u Items Required 

1 Block of Styrofoam Plastic 
or Foam Polystyrene (A) 

1 Electric Bottle Cutter (B) 

1 Thin Nichrome Wire (C) 



Dimensions 

Approximately 

4 cm x 10 cm x 10 cm 

(I/F2) 

0.02 cm diameter, 
35 cm long 



-194- 



(2) Rigid Connector 1 

(3) Flexible Connector 1 
b. Constructi on 



Box of Toothpicks (d) Approximately 250 

Package of Pipe C eaners (E) Approximately 25 



(1) Ball 




Terminals of Electric 
Bottle Cutter (B) 



T 



Thin Nichrome 
Wire (C) 




Styrofoam (A) 




Construct the electric bottle 
cutter (B) according to 
directions given in (I/F2) . 
Substitute the thin nichrome 
wire (0.02 cm diameter) for 
that described and stretch 
it tightly between the terminals, 
Connect the terminals to a six 
volt battery or a transformer 
that steps line current down 
to about six volts. 

Form the Styrofoam (A) into 
small balls, First, cut the 
block into cubes, determining 
the sizes according to the 
element each represents: 

H - 1 . 5 cm on a side 

C - 3 c m " " " 

- 3 c m 

Si - 4 cm 

To cut a precise straight line, 
brace a large wooden block 
against the base of the bottle 
cutter, with one edge as far 
from the taut wire as the width 
of the desired cut. Push the 
Styrofoam block (A) down on 
the hot, taut wire to slice 
it, holding it against the 
wooden block which acts as a 
guide. 



Wood Block 



-195- 




Carefully cut the corners off 
each cube to approach the 
shape of a sphere. 



(2) Rigid Connectors 



Sigma Bonds 




Hydrogen 



(3) Flexible Connectors 



Pi Bond 




Last, shape the trimmed cubes 
with the fingers more exactly 
into spheres. 

For clarity in the finished 
models, paint the balls with 
tempera (poster paint) to 
which a small amount of 
dissolved soap has been added. 
Use the following colors to 
represent : 

H - white 

C - black 

- red 

Stick toothpicks (D) into the 
Styrofoam balls to represent 
sigma bonds between atoms, as 
in the ethane molecule ^Hg) 
represented here. 



Use pairs of pipe cleaners (E) 
cut to approximately 5 cm 
lengths to represent pi bonds 
between atoms, as in the ethene 
(ethylene; C2H4) molecule 
represented here. 



Pi Bond 



-196- 




When triple bonds (one sigma 
and two pi bonds) are to be 
represented, dye the two pairs 
of pipe cleaners different 
colors for clarity. This 
diagram represents a molecule 
of ethyne (acetylene; C2H2) . 



c. Notes 



(i) If commercially manufactured Styrofoam or foam polystyrene balls are easily 
available, they may be substituted for the hand-made balls described here. 

(ii) The scale of approximate sizes of the balls used in these models is based 
on the atomic radii for stable compounds listed in the Periodic Table of the 
elements, for example: 





Atomic Radius 


Approximate 


Element 


in Angstroms 


Ratio 


C 


0.77 


2 


N 


0.75 


2 





0.73 


2 


H 


0.32 


1 



(iii) If Styrofoam or foam polystyrene is not available, modeling clay (plasticine) 
may be used for the balls and painted appropriate colors. However, once the clay 
balls are painted, repeated puncturing of them with toothpicks will disfigure them. 
Thus, it is recommended that they be used only to make permanent demonstration 
models . 

(iv) Pipe cleaners or match sticks may be substituted for the toothpicks if 
desired. 

(v) A kit for teacher use should contain: 

2 dozen balls representing Carbon 



2 dozen 

2 dozen 

1 dozen 

1 dozen 

1 dozen 



Hydrogen 

Oxygen 

Halogens 

Nitrogen 

Sulfur 



several dozen each straight and flexible connectors, 

This would provide sufficient materials for constructing demonstration models 
in the classroom. The same guantities listed above would be adeguate for laboratory 
use for from one to four students. 



-197- 



(vi) The use of molecular models in the study of chemistry can enhance thestudents' 
understanding of and ability to predict the various properties and interactions of 
elements and compounds. These ball and stick models illustrate, roughly, the 
relative bond angles, sizes and positions of atoms within a molecule in a clear and 
simple form. They are not, however, scale representations of bond lengths or atomic 
molecular sizes and shapes. In order to demonstrate the mathematical relations of 
electrons in a given molecule, it will be necessary to employ a different style 
model, that which is described in the next section. 

(vii) The color code * used in these models is as follows: 
Hydrogen - white 
Carbon - black 
Oxygen - red 
Nitrogen - blue 
Sulfur - dark yellow 
Flourine - light green 
Chlorine - dark green 
Bromine - orange 
Iodine - brown 
Phosphorous - violet 
Silicon - light yellow 



*From the Portland Project Committee, Teacher Guide, Chemistry of Living Matter, 
Portland, Oregon: Portland Project Committee, (1971, p 1/. 



-19E 



SKELETAL MODELS 



Bl. Molecular Model Units* 




Assembled View 



C^3> 



cz> 




1) Tubing 



C^D 



<o=> 



(2) Valence Cluster 



(3) Connector 



Exploded View 



*Adapted from George C. Brumlik, Edward J. Barrett, and Reuben L. Baumgarten, 
"Framework Molecular Models, " Journal of Chemical Education , XLI (1964), pp 221-223. 



-199- 



a. Materials Required 
Components 
(1) Tubing 



(3) Connector 



b. Construction 



(1) Tubing 



2) Valence Cluster 




Qu Items Required 

Milk Straws (Paper or 
Plastic) (A) 

Tempera (Poster) 
Paints (B) 



Pipe Cleaners (C) 

Pipe Cleaners (D) 
Finishing Nails (E) 

Soft Iron Wire (F) 




Glue 



Dimensions 

0.4 cm diameter, 
approximately 20 cm long 

Black, white, red, 
yellow, green, blue, 
orange 



Approximately . 1 cm 
diameter, 1 . 5 cm long 

Approximately 0.05 cm 
diameter 



Mix a small amount of liquid 
or dissolved soap with the 
tempera paints (B) to reduce 
their surface tension. Using 
this mixture, paint several 
milk straws (A) according to 
the atom they are to represent: 

Carbon - black 

Hydrogen - white 

Oxygen - red 

Nitrogen - blue 

Sulfur - dark yellow 

Bromine - orange 
[Consult Note (ii) for 
additional colors . ] 

Cut the straws into various 
lengths depending upon the 
scale used and bond represented. 

Bend a pipe cleaner (C) into the 
shape desired, and glue the 
joint in the middle. When the 
glue has dried, adjust the 
angles of the arms of the 
connector to suitable angles. 



Bend 



-200- 



Vertical 
Arm 



Horizontal 
Arm 




Make tetrahedral (4 arms) shapes 
with the angles of the arms at 
about 109' . 



Make trigonal bipyramid (5 arms) 
shapes. Arrange the angles 
between the three horizontal 
arms to 120'. Adjust the two 
vertical arms at right angles 
to the horizontal arms. 



Vertical 
Arm 



Horizontal 
Arm 




Construct octahedrons (8-pointed), 
Adjust the angles between the 
four horizontal arms to 90'. 
Arrange the two vertical arms 
at right angles to the horizontal 
arms, 



(3) Connectors 



9t222ZZZ2Z^ 



Pipe Cleaner 
(C) 



Nail (E) 




Soft Wire (F) 



c. Notes 



Construct straight connectors 
to represent bonds between atoms 
by wrapping a pipe cleaner (C) 
around a nail (E) . Vary the 
length of pipe cleaner used 
according to the tightness 
desired. 

To make angular connectors to 
be used to complete various 
structures, bend a pipe cleaner 
(C) in half. Then wrap soft 
wire (F) around the pipe cleaner 
and bend the assembly to a 90' 
angle . 



(i) These units can be used to build models of almost any molecule, The valence 
clusters represent atomic nucleii, the intersection of the arms representing the 
center of the atom. The tetrahedral (4-armed) valence cluster depicts bond angles 



-201- 



of approximately 109°, for sp^ hybridized orbitals or atoms with eight electrons in 
their valence shell. The five-armed valence cluster can depict sp^ hybridization, 
with 120' bond angles, for atoms engaged in (pi) bonds, as well as d sp^ 
hybridization, with 90° and 120° bond angles for atoms with ten atoms in their 
valence shell . The six-armed valence cluster can represent sp hybridization with 
bond angles near 180°, or d sp hybridization for atoms with twelve electrons in 
their valence shell. The straight connector depicts 6 (sigma) bonds between like 
or unlike atoms . 

Electrons, whether bonded or unshared, are represented by the straws, color 
coded and cut to scale. 

The straws in a completed molecular model represent covalent radii of 
bonding atoms, and van der Waals radii in the non-bond direction. 

(ii) Below are charts* to guide the coloring and cutting of straws to represent 
covalent radii or van der Waals radii. Any convenient scale may be used to 
simulate the Angstrom unit (A) measurements of these forces. For example, a scale 
of 10 cm/A produces large models ideal for lecture demonstrations, while a scale 
of 2 cm/A yields smaller models suitable for student use. 







Length of 


Length of 








Straw in cm 


Straw in cm 


Color 




Atomic Cbvalent 


(Scale: 
10 cm/A) 


(Scale: 


of 


Bond 


Radii (A) 


2 cm/A) 


Straw 












C — single 


0.77 


7.7 


1.5 




C - double 


0.67 


6.7 


1.3 


black 


C - triple 


0.60 


6.0 


1.2 




O - single 


0.74 


7.4 


1.5 




O - double 


0.62 


6.2 


1.2 


red 


O - triple 


0.55 


5.5 


1.1 




N - single 


0.74 


7.4 


1.5 




N - double 


0.62 


6.2 


1.2 


blue 


N - triple 


D.55 


5.5 


» 1.1 





*Adapted from the Portland Project Committee, Teacher Guide, Chemistry of Living 
Matter, (Portland, Oregon: Portland Pro ject Committee, 1971), pp 8-18. 



-202- 



Bond 
(single) 


Atomic Covalent 
Radii (A) 


Length of 
Straw in cm 
(Scale : 
10 cm/A) 


Length of 
Straw in cm 

2 cm/A) 


Color 

of 
Straw 












H 


0.30 


3.0 


0.6 


white 


F 


0.64 


6.4 


1.3 


light green 


Si 


1.17 


11.7 


2.3 


light yellow 


P 


1.10 


11.0 


2.2 


violet 


S 


1.04 


10.4 


2.1 


dark yellow 


CI 


1.00 


10.0 


2.0 


dark green 


Br 


1.14 


11.4 


2.3 


orange 


I 


1 1.33 


13.3 


2.7 


brown 



Atom 



Cl 
Br 



Van der Waals* 

o 

Radii (A) 

1.2 

1.40 

1.35 

1.85 

1.80 

1.95 

2.15 

1.5 

1.9 



Length of 
Straw in cm 
(Scale: 
10 cm/A) 

12.0 
14.0 
13.5 
18.5 
18.0 
19.5 
21.5 
15.0 
19.0 



Length of 
Straw in cm 
(Scale: o 
2 cm/A) 



2.4 
2.8 
2.7 
3.7 
3.6 
3.9 
4.3 
3.0 
3.8 



Color 
of 
Straw 



white 

red 

light green 

dark yellow 

dark green 

orange 

brown 

blue 

violet 



-203- 



B2 . Single Bond Structures* 




(1) Carbon-Carbon 




(5) H 2 (Water) 



(2) Carbon-Oxygen 





(4) CH 4 (Methane) 



*Adapted from the Portland Project Committee, Teacher Guide, Chemistry of Living 
Matter, (Portland, Oregon: Portland Project Committee, 19/1) , pp 19-28. 



-204- 



a. Materials Required 
Components 

(1) Carbon-Carbon 

(2) Carbon-Oxygen 



(3) Carbon-Hydrogen 



(4) CH 4 (Methane) 



(5) H 2 (Water) 



b. Construction 



(1) Carbon-Carbon 



0.77A 



Qu 

: 

2 

: 




(2) Carbon-Oxygen 



(E) 0.74A 



Items Required 
Straight Connector (A) 
Black Straws (B) 

Straight Connector (C) 
Black Straw (D) 
Red Straw (E) 

Straight Connector (F) 
Black Straw (G) 
White Straw (H) 

4-armed Valence Cluster (I) 



Dimensions 


X/Bl 




1.5 


cm 


X/Bl 




1.5 


cm 


1.5 


cm 


X/Bl 




1.5 


cm 


3.0 


cm 



X/Bl 



Carbon-Hydrogen Bonds (F,G,H) 4.5 cm 
[see (3) above] 

4-armed Valence Cluster (J) X/Bl 

Red Straws (K) i 5 cm 

Red Straws (L) 2.8 cm 

White Straws (M) 3.0 cm 

Straight Connectors (N) X/Bl 



Straight Connector (A) 



i r 



0.77A (D) 



To represent this single covalent 
bond between like atoms, cut two 
black straws (B) to a scale 
representation of the single 
bond covalent radius of carbon 
(X/BI), Note (ii) . For example, 
cut the straws to 1.5 cm for 
a scale of 2 cm/A. Join these 
two straws with a straight 
connector (A) . 

To construct this model of a 
single covalent bond between 
unlike atoms, cut one black 
straw (D) to represent the 
single bond covalent radius for 
carbon (1.5 cm, for example) 
and a red straw to represent 
the single bond covalent radius 
for oxygen (E) (1.5 cm) . Connect 



-205- 



(3) Carbon-Hydrogen 



(G) 0.71k 



. 0.3A 1.2A 

\ 'I t 



L 



■L 



Van der Waals 



radius of H 
Nucleus of H atom 

Covalent radius of H 



4 ) CH 4 (Methane) 




these two straws with a straight 
connector (C) . 

Construct the carbon-hydrogen 
bond to include a representation 
of the van der Waals radius for 
hydrogen. Cut one black straw 
(G) to indicate the single bond 
covalent radius for carbon. Cut 
one white straw (H) to show the 
covalent radius of H (0.6 cm) 
plus the van der Waals radius of 
H (2.4 cm) . Draw a line around 
the white straw at the inter- 
section of these two values to 
indicate the position of the 
hydrogen nuculeus, then join the 
black and white straws with a 
straight connector (F) . 

Construct four carbon-hydrogen 
bonds (F,G,H) as described 
above. Join them all together 
at the carbon end by sliding 
each onto an arm of the four- 
armed valence cluster (I) and 
pushing all the straws together 
so that the connectors do not 
show. 

Cut two red straws (L) to 
represent the van der Waals 
radius of (2.8 cm). These 
will represent two unshared 
electron pairs, Cut two red 
straws (K) to indicate the 
single bond covalent radius 
of (1.5 cm) . Use a straight 
connector (N) to join each of 
these with a white straw (M) 
representing the covalent and 



-206- 



van der Waals radii of H (3.0 cm) . 
Connect the two red straws and 
two - H bonds with a four-armed 
connector (J) as illustrated. 



c. Notes 



(i) Single covalent bonds between like atoms, such as the carbon-carbon bond, 

may also be represented by one 



C 



C 



straw, appropriately colored, 
cut to twice the covalent radius. 
Thus, the carbon-carbon bond 



would be represented by one black straw, 3 cm long. 

(ii) Unlike thespace-f illing models of X/Al, these models do not show molecular 

shape. The shape of the constituent atoms within a molecule must be imagined; 

the scale and orientation of the parts of the model show bond lengths, bond angles, 

and bond thicknesses in reasonably accurate scale. 

(iii) These skeletal molecular models are based on atomic orbital geometry, which 
deals with the behavior of electrons in paths, or orbitals, in the space around 
the nucleus of an atom. For a complete discussion of electrons, nucleii, and 
orbitals, consult recent chemistry texts, such as Chemical Bond Approach Project, 
Chemical Systems, (Webster Division McGraw-Hill Book Company, 1964), Chapter 10. 



-207- 



B3 . Double Bond Structures* 



1) H 2 C = CH 2 
Ethene) 





(2) H 



2 C =0 
Formaldehyde) 



Adapted from the Portland Project Committee, Teacher Guide, Chemistry of Living 
Matter, (Portland, Oregon: Portland Project Committee, i9/l) pp 28-36. 



-208- 



(3) C 6 H 6 

Benzene) 



d 




D 



(4) H 2 C = C = CH2 
(Allene) 




-209- 



a. Materials Required 



Components 


Qu 


Items Required 








Dimens: 


(1) H 2 C=CH 2 


2 


5-armed Valence 


CI 


usters 


(A) 


X/Bl 


(Ethene) 


4 
3 
4 


C-H Bonds (B) 
Black Straws (C) 
Black Straws (D) 








4.5 cm 

2.6 cm 
3 . cm 




4 


Angular Connectors 


(E) 




X/Bl 


(2) H 2 C=0 


2 


5-armed Valence 


CI 


usters 


(F) 


X/Bl 


(Formaldehyde) 
















4 


Angular Connectors 


(G) 




X/Bl 




2 


C-H Bonds (H) 








4.5 cm 




3 


Red Straws (I) 








1.2 cm 




3 


Black Straws (J) 








1.3 cm 




2 


Red Straws (K) 








3 . cm 




2 


Black Straws (L) 








3 . cm 




2 


Red Straws (M) 








1 . 5 cm 




3 


Straight Connectors 


; (N) 




X/Bl 



(3) Ccflc 18 5-armed Valence Clusters (0) X/Bl 
(Benzene) 

6 C-H Bonds (P) 4.5 cm 

18 Black Straws (Q) 2.6 cm 

12 Black Straws (R) 3.0 cm 

(4) H 2 C=C=CH 2 2 5-armed Valence Clusters (S) X/Bl 
(Allene) 

1 6-armed Valence Clusters (T) X/Bl 

4 C-H Bonds (U) 4.5 cm 

6 Black Straws (V) 2.6 cm 

8 Black Straws (W) 3.0 cm 

8 Angular Connectors (X) X/Bl 

b. Construction 



(1) H 2 C=CH 2 (Ethene) First construct four C-H 

bonds (B) (X/B2) . Then complete 
the H 2 C=CH 2 molecule as shown. 
Use three 2 . 6 cm black straws 
(C) to represent double bond 
formation between like atoms. 
The central black straw (C) 



-210- 




represents the a bond. The 
two outside sections of black 
straws (C) represent the two 
arms of the bond, the 
thickness of which is shown 
by the four 3.0 cm black 
straws (D) . Their length 
represents the single bond 
covalent radius of carbon. 



(2) H 2 C=0 (Formaldehyde) 



(I I —I 

^_ 

(I) (N) (J) 




Construct this model showing 

double bond formation between 
like atoms. First, construct 
three C=0 bonds representing 

the double bond radii C (J) 
and (I), as shown. Make two 
C-H bonds (H) (X/B2) . 

Use the 5-armed valence clusters 
(F) and angular connectors (G) 
to join the straws. Indicate 
the thickness of the it bond by 
red straws on the oxygen side, 
black straws on the carbon side. 



-211- 



(3) C fi H fi (Benzene) 



^jfe,H> 



(0) Modified 




One corner, exploded view 



(4) H 2 C=CH 2 (Allene) 



Cut off and discard one 
horizontal and one vertical arm 
from each of twelve 5-armed 
valence clusters (0) to form 
3-cornered clusters . 




Make six C-H bonds (X/B2) (P) . 
Construct the three layered 
model as shown. Use the 
twelve 3 . cm black straws (R) 
to represent the thickness of 
the bonds (twice the single 
covalent radius of carbon) . 
Use the eighteen 2 . 6 cm black 
straws (Q) to represent the 
bond lengths (twice the double 
covalent bond radius of carbon) . 
The shared-bond aspect of the 
ring structure often pictured: 




is represented in the model by 
the three-layered structure. 

Construct four C-H bonds (U) . 
Use one 6-armed valence cluster 
(T) , as well as two 5-armed 
clusters (S), to connect the 
the components of the 
H2C-C-CH a (allene) molecule. 



-212- 




Place the 6-armed cluster (T) 
as shown to indicate that the 
middle carbon atom is bonded 
to each of the side carbons. 



c. 



Notes 



(i) These four examples of double bond models illustrate some of the complex 
double bond forms that can be built. By applying the principles thus illustrated, 
it should be possible to construct almost any simple or complex double bonded 
molecule. 

(ii) because the forces holding two nucleii together in a double bond are greater 
than those in a single bond, the nucleii are closer together, Thus, the straws 
representing the C=C or C=R covalent distance are shorter than those representing 
the C-C or C-R distance. 

(iii) In the ^0=0 (formaldehyde) molecule, the slightly longer tubing representing 
the bond thickness at the carbon atom than at the oxygen atom indicates a certain 
strain on the double bond. The covalent radius of oxygen is used to model the 
unbonded electrons, rather than the van der Waals radius as in the model of water, 
because the C=0 bond "pulls" or distorts the oxygen electron cloud. C=N bonds 
may be constructed just as C=C and C=0 bonds; blue tubing represents N. 



-213- 



B4 . Triple Bond Structure* 




( 1) HC = CH 

(Acetylene) 



a. Materials Required 

Components 

(1) HC=CH 

(Acetylene) 



Qu 
2 



Items Required 



Dimensions 



6-armed Valence Clusters (A) X/Bl 

Angular Connectors (B) X/Bl 

C-H Bonds (C) 4.5 cm 

Black Straws (D) 2.4 cm 

Black Straws (E) 3.0 cm 



*Adapted from the Portland Project Committee, Teacher Guide, Chemistry of Living 
Matter, (Portland, Oregon: Portland Project Committee, 1971), pp 36-3/. 



-214- 



b. Construction 



(1) HC=CH (Acetylene) 




First make two C-H bonds (C) 
(X/B2): Then use two 6-armed 
valence clusters (A) and eight 
angular connectors (B) to 
connect the parts of the HC=CH 
(acetylene) molecule as shown. 
The 2 . 4 cm black straws (D) 
indicate the length of the 
triple bond, and are cut to 
represent twice the triple 
covalent bond radius for carbon. 
Bond thickness is indicated by 
the 3 . cm straws (E) or twice 
the single bond radius for 
carbon . 



c.Notes 

(i) Because the forces holding two nucleii together in a triple bond are 
stronger even than those of a double bond, the nucleii are closer together. Thus, 
the straws representing the C=R covalent distance are shorter than those representing 
the C=R distances . Nucleii involved in sp hybridization with triple bond formation 
are represented in the model by the 6-armed sp valence cluster. 

(ii) In the HC=H (acetylene) model, the central carbon-carbon bond represents 
the 6 bond. The four outside sections of black straws represent two double-armed 
bonds . 



-215- 



35. Geometric Structures 



(1) Straws 




a. Materials Required 
Components 
(1) Straws 



g u Items Required 

Paper or Plastic 
Milk Straws (A) 

Pipe Cleaners (B) 



b. Construction 
(1) Straws 



Dimensions 

Approximately 
. 4 cm diameter 

Approximately 
3 cm lonq 



Cut the straws (A) to any 
convenient length, 5 cm, for 
example. Paint the straws, 
if desired, with poster (tempera) 
paints to which a small amount 
of dissolved soap has been added. 



*Adapted from D.C. Hobson and C. V. Platts, "Milk-Straw Molecular Models, 
School Science Review, CLXIH ( 1 9 6 6 ) pp 694-701 . 



-216- 



(2) Connectors 



1 



Bend the cut pipe cleaners (B) 
to form right angles. 




Insert the pipe cleaners (B) 
into the straws (A) , as shown, 
to form secure connections. 



C. Notes 

(i) By selecting appropriate numbers of straws and connectors, a variety of 
geometric forms may be built. 



-217- 



C. CRYSTAL STRUCTURE MODELS 



CI. Crystalline Packing Models* 




(1) Body-Centered 
-Cubic Unit Cell 





(2) Face-Centered 
Cubic Unit Cell 



(3) Closely-Packed 

Hexagonal Unit Cell 



* Adapted from J. W. Coakham, W. Evans, and H. Nugent, 
School Science Review, CLXXIV (1969), pp 61-71. 



'Introducing Crystal Structures, 



-218- 



a. Materials Required 

Components 

(1) Body-Centered 
Cubic Unit Cell 



Qu 



(2) Face-Centered 14 
Cubic Unit Cell 

(3) Closely-Packed 17 
Hexagonal Unit 

Cell 

b. Construction 



Items Required 

Styrofoam or Foam 
Polystyrene Spheres 

Styrofoam or Foam 
Polystyrene Spheres 

Styrofoam or Foam 
Polystyrene Spheres 



(1) Body-Centered Cubic Unit Cell 




(A) 



(O 



Dimensions 

Approximately 4 cm 
diameter 

Approximately 4 cm 
diameter 

Approximately 4 cm 
diameter 



Make the spheres (A) from 
Styrofoam or foam polystyrene 
(X/Bl) or purchase spheres 
from a commercial source. Use 
the nine spheres to represent 
the atoms of the crystal 
according to the "exploded" 
diagram. Place four spheres 
in the top and bottom layers, 
and one in the middle. Use 
toothpicks, pipe cleaners, 
match sticks, or cement to 
hold the spheres together, 



(2) Face-Centered Cubic Unit Cell 




Use this exploded diagram as 
a guide for building the 
face-centered cubic unit cell 
from 14 spheres (B) . Place 
five spheres in both top and 
bottom layers, and four spheres 
in the middle layer. 



-2 19- 



(3) Closely-Packed Hexagonal Unit Cell 




Use seventeen spheres (C) as 
illustrated to build the 
closely-packed hexagonal unit 
cell. Place seven spheres in 
the top and bottom layers, with 
three in the middle layer. 



c. Notes 

(i) The models described demonstrate three-dimensional patterns found in 
crystals of metals, where the atoms are all of one size and the bonding forces 
are egual in all directions. As with previous models, the use of molecular models 
aids the student in both understanding the structure and predicting the character- 
istics of the substances studied. 

(ii) If it is necessary to construct crystal models showing different ion sizes, 
smaller or larger Styrofoam spheres may be used. For example, ionic crystal models 

may be constructed using 
spheres 2 cm in diameter for 
anions, and . 2 cm diameter 
O for cations, 




Anion 
2 cm 



Cation 

0.2 cm 



(iii) These models may be also used to demonstrate such aspects of crystal 
structures as coordination number, most closely-packed planes and Miller Indeces, 

(iv) For further discussions on the application of these models to the study 
of the molecular structure of crystals, consult J, W. Coakham, W. Evans, and 
H. Nugent, "Some Aspects of Crystal Structure, Part I," S chool Science Review, 
CLXXIX, pp 339-350. 



-2 2 0- 



D. KINETIC-MOLECULAR MODEL 



Dl. Kinetic Theory Model* 




CO 




(1) Tray 



(2) Dowel 



-(3) Marbles 



a, Materials Required 
Components 
(1) Tray 



(2) Dowel 

(3) Marbles 

b. Construction 
(1) Tray 



(2) Dowel 



(3) Marbles 



Qu Items Required 

1 Wood (A) 

2 Wood (B) 
2 Wood (C) 



1 



Wooden Dowel (D) 



250 Marbles or Glass Beads (E) 



5 Marbles or Glass Beads (F) 



Dimensions 

1 cm x 30 cm x 30 cm 

2 cm x 2 cm x 26 cm 
2cmx2cmx30cm 

Approximately 1.5 
x 40 cm 

Approximately 1 . 0-1 . 5 
cm diameter 

Larger than the others 



Nail or glue the four wood 
strips (B and C) to the flat 
wood square (A) to form a 
tray. Varnish the tray inside 
and out to provide a slick 
inside and outside surface. 

Select a dowel (D) to support 
one end of the tray. 

Place the marbles or plastic 
or glass beads (E) in the tray. 
Use all of them to represent 
the molecules in a solid or 
liquid. Use only 40 - 50, 



* Adapted from I. D. Taylor, "Kinetic Theory Nodels," School Science Review, 
CLXIII(1963), pp 780-783. 



-221- 



plus the few larger marbles (F) , 
to represent the molecules in 
a gas. 



c . Notes 



(i) To demonstrate, two-dimensionally, the kinetic activity of molecules in 
matter, place all the marbles in the tray. Rest one end of the tray on the dowel 

so that the marbles all roll 
to the opposite end, packing 
into a regular structure 
with each marble, or "molecule" 
touching six neighbors. 




(ii) When the tray is at rest, none of the "molecules" move, representing the 
theoretical condition of matter at absolute zero. when the tray is gently agitated 
back and forth, the "molecules" begin to vibrate and to show "thermal expansion". 
They occupy a larger volume, but generally retain the same relative position. 
Occasionally a few molecules jump clear of the surface, representing the slight 
vapor pressure of a solid. 

(iii) As the tray is agitated still harder, with greater amplitude, the "solid" 
"melts" with the "increase in temperature" (increase in kinetic energy). The 

molecules slip out of place, 
the volume increases, and 
more molecules jump away from 
the surface. 




By slowing down the rate and amplitude of vibration, the "liquid" can be 
converted back to a "solid". Slowing the vibration gently represents gradual 
cooling and results in a regular structure. If however, the vibration suddenly 
ceases, rapid cooling is demonstrated. The resulting "solid" shows an irregular 
structure with many imperfections. 

(iv) For a demonstration of a "gas", most of the molecules are removed, and 
the tray is agitated more rapidly than for the "solid" or "liquid". All the 



-222- 



molecules move rapidly and 
randomly about, traveling large 
distances before colliding 
with one another. A few larger 
marbles, added to the "gas", move 
with small, irregular, jerky 
motions, representing the 
Brownian motion of dust or 
smoke particles in air. 

(v) If a clean glass tray and overhead projector is available, the model may be 
projected on a screen for a large class to see. The "molecules" show on the 
screen as shadows. 




-223- 



XI. CHROMATOGRAPHIC APPARATUS 

Chromatography, a powerful analytical technique of recent development, may be 
performed with relatively simple apparatus. It is based upon the differential migra 
tion of solutes in a liquid or solid medium and maybe used for both qualitative and 
quantitative analysis of solutions. 

A. QUALITATIVE CHROMATOGRAPHIC APPARATUS 

This section includes chranatographic devices employing paper as the stationary 
medium and briefly describes a few techniques for using these devices to identify the 
components of a mixture. 

B. QUANTITATIVE CHROMATOGRAPHIC EQUIPMENT 



This section describes a device that allows for the separation of the components 
of a mixture as well as the recovery of individual components for further experimenta- 
tion or purification. 



-224- 



A. QUALITATIVE CHROMATOGRAPHIC APPARATUS 



Al . Horizontal Paper Chromatography Device 




(1) Paper 



(2) Support 



a. Materials Required 
Components 

(1) Paper' 

(2) Support 

b. Construction 
(1) Paper 



(2) Support 



Qu I tems Required 
1 Filter Paper (A) 

1 Petri Dish (B) 



Dimensions 

Approximately 10 cm 
diameter or larger 

Slightly smaller 
than filter paper 



Use a circle or square of 
filter paper (A) as the medium 
for the chromatogram. 

Select a petri dish or other 
shallow container (B) just 
slightly smaller than the 
paper (A) on the support (B) . 

C.Notes 

(i) This apparatus can be set up almost instantaneously for rapid, qualitative 
work. A drop of a colored solution to be analyzed is placed in the center of the 
paper. Then, successive, small drops of the eluting solvent are dropped on top 

of the original drop. The 
solution spreads radially, and 
as separation of components 
occurs, concentric rings of 
color will appear on the paper. 




-225- 



(ii) As an example of a test solution, a drop of black or blue-black, washable 
ink may be used. The eluting solvent in this case could be water, methanol 
(methylated spirits) or 70% ethanol. 

(iii) Chromatography paper, white paper towels, blotting paper, newsprint paper, 
or other white or light-colored, coarse-grained paper may be substituted for the 
filter paper (A) . 



-226- 



A2 . Horizontal Paper Chromatography Device 



(1) Paper 



(2) Support 






-^ (3) Cover 



a. Materials Required 
Components 

(1) Paper 

(2) Support 

(3) Cover 

b. Construction 

(1) Paper 



q u Items Required 

1 Filter Paper (A) 

1 Cup or Jar (B) 

1 Glass Jar or Bowl (C) 



Dimensions 

Approximately 10 cm 
diameter or larger 

Slightly smaller than 
filter paper 

To cover paper and 
support 



Take a circle or square of 
filter paper (A) or suitable 
substitute and cut a tongue 
across the paper to within 
about 1 cm of the center of the 



*Adapted from A. V. Jones, "Chromatography for Junior Schools," School Science 
Review, CLXXIX: (1970), 298-300. 



-227- 



paper. Bend the tongue down at 
a right angle to the paper (A) . 

(2) Support Select a small cup or jar (B) 

just slightly smaller than the 
paper (A) . Rest the paper (A) 
on the jar (B) with the paper 
tongue extended into the jar. 

(3) Cover Select a large glass jar or 

bowl (C) to cover the support 
and paper. Invert the cover to 
enclose the other two compo- 
nents . 

c. Notes 



(i) This apparatus, while only slightly more complex than that in the previous 
section, has the added advantage that, once set up, it may be left to stand for 
some time. A spot of test solution (e.g., ink or a concentrated extract made from 
plant flowers, leaves , stems, or roots) is placed at the center of the paper (A) . 
Then the small jar (B) is filled to within about 2 cm of the top with solvent (e.g., 
water or alcohol) . When the paper tongue is placed in the solvent, the liquid 
will soak up the tongue to the test spot, and beyond. The components of the test 
solution separate out, in rings, as the solvent progressively soaks the paper. 
Covering the apparatus with a bowl or jar (C) helps prevent evaporation of the 
solvent before it has had time to soak the paper. 

(ii) The experiment continues until the solvent front reaches to within about 
1 cm of the edge of the paper, or until it is apparent that it has stopped moving. 
The paper is then removed from the apparatus and rapidly dried, using the drying 
lamp (IX/A3), a fan, or other source of dry heat or moving air. 



-228- 



A3 . Horizontal Paper Chromatography Device * 



(1) Paper 



(2) Support 




<3) cc 



a. Materials Required 
Components 
(1) Paper 



(2) Support 

(3) Cover 



Qu I tems Required 
1 Filter Paper (A) 

1 String (B) 



1 Cup or Jar (C) 



Glass Bowl or Jar (D) 



Dimensions 

Approximately 10 cm 
diameter or larger 

Approximately . 2 cm 
diameter, 5-10 cm 
long 

Slightly smaller than 
filter paper (A) 

To cover paper (A) and 
support (C) 



-2 2 9- 



b. Construction 
(1) Paper 




Cut Out 
Slits 



Take a circle or square of 
filter paper (A) or suitable 
substitute and cut several slits 
radiating from the center as 
shown. Punch a small hole in 
the center and secure a piece of 
string (B) with a knot, to act 
as a wick. 



(2) Support 



(3) Cover 



Select a small cup or jar (C) 
just slightly smaller than the 
paper (A) . Rest the paper (A) 
on the rim of the jar (B) so 
that the string wick (C) extends 
into the jar. 

Select a large glass jar or bowl 
(D) to cover the support and 
paper. Invert the cover to 
enclose the other components. 



c. Notes 



(i) This apparatus is used in the same fashion as the preceding device. How- 
ever, the slits in the paper 
allow for more than one colored 




spots of 

Colored 

Substances 



substance or test solution to 
be used simultaneously. The 
spots are placed inside the "V" 
of the slits, which prevent the 
colors from merging. 



-230- 



A4 . Vertical Paper Chromatography Equipment 



(1) Paper 



(2) Solvent 
Container 




(3) Cover 



a. Materials Required 
Components 

(1) Paper 

(2) Solvent 



Qu I tems Required 

1 Chromatography 

Paper (A) 



1 



Beaker, Bowl or Jar (C 



Dimensions 

Approximately 15 cm 
x 15 cm 

To contain paper (A) 
when rolled into tube 



(3) Cover 



1 Glass Jar or Bowl (D) 



To fit on or over 
Solvent Container (C) 



-231- 



b. Construction 



(1) Paper 




With a pencil, draw a faint 
line approximately 2 - 3 cm 
from one edge of the paper (A) . 
Use this line as a guide for 
locating the spots of solution 
or solutions to be tested. Make 
the spots as small as possible 
and about 2 cm apart . 



Spots 




• 






Roll the paper (A) loosely into 
a tube. Secure the edges 
together with the paper clips 
(B) such that the edges do not 
touch or overlap. 



(2) Solvent Container 



(3) Cover 



Set the rolled paper (A) into 
the beaker, bowl, or jar (C) 
and pour solvent into the 
container (C) to a height of 
about 1 cm. 

Rest a large glass jar or bowl 
(D) on or over the solvent con- 
tainer (C) to prevent evapora- 
tion of the solvent. 



-232- 



c. Note s 

(i) If chromatography paper is not available, white paper toweling or blotting 
paper may be substituted. 

(ii) When this apparatus is in use, the solvent front migrates up the paper, (by 
capillary action) resulting in the separation of the components of the test spot. 
This is allowed to continue until it has reached to within several cm of the top 
of the paper or until it is apparent that the solvent front will move no further 
(when the rate of capillary action is in eguilibrium with the rate of evaporation) . 
The paper is then removed from the apparatus and dried, and the final locations of 
the color spots may be circled with pencil for easy identification. 

(iii) This apparatus is also suitable for performing separation of colorless 
substances, as long as the completed chromatogram can be treated in some way to 
make visible the final location of the component of the substances. For example, 
proteins, while generally colorless, may separate in this fashion. The dried 
chromatogram is then sprayed with a ninhydrin solution, which reacts with the 
amino acids in their final locations, making them visible as bluish spots or 
smudges . 

(iv) It is possible, with this apparatus, to submit a substance to chromoto- 
graphic separation by two different solvents on the same sheet of paper. To run 

such a two-dimensional chromato- 



* 



Direction 
of First Run 



-ip- 



/ Separation 
/ At' End of 
X ■ Firs 



:st Run 



gram, a spot of the substance 
is placed at the intersection 
of two lines drawn on the 
paper and treated as described 
above, with one solvent. At 
the end of the first run, the 
chromatogram is removed from 
the apparatus and dried. 



spot of 
Substance 



-233- 



Final Separation 



Direction of 
First Run 




Direction 

of Second 

Run 



Then the paper is rotated 90° 
and again rolled into a tube, 
with the first separation at 
the bottom edge of the tube. 
This tube is run a second time 
with a second solvent. Thus, 
it is possible to effect a 
more complete separation than 
is possible with one solvent 
alone. 



(v) A complete discussion of techniques and substances appropriate to chromato- 
graphic separation is beyond the scope of this guidebook. For further information, 
texts and resources on biochemistry, chemistry, and chromatography should be 
consulted. 



-234- 



A5 . Vertical Strip Paper Chromatography Equipment 



(1) Frame 




(3) Cover 



(2) Solvent 

Container 



a. Materials Required 
Components 
(1) Frame 



(2) Solvent 



(3) Cover 



Qu I tems Required 

2 Wood (A) 

2 Wood (B) 

4 Wood (C) 

1 Wood or Masonite (D) 

1 Thin, Stiff Wire (E) 

1 Cup or Jar (F) 

1 Plastic Bag (G) 



Dimensions 

1 cm x 1 cm x 8 cm 

1 cm x 1 cm x 10 cm 

1 cm x 1 cm x 20 cm 

6 cm x 10 cm x 0.2 cm 

Approximately 11 cm 
long 

Approximately 4 cm 
high, to fit inside 
frame 

To fit loosely over 
frame 



-235- 



b. Construction 
(1) Frame 




With nails and glue, secure the 
frame parts (A), (B) , (C) , and 

(D) as shown. Secure the wire 

(E) to the frame, about 2 cm 
from the top, with two small 
nails . 



(2) Solvent Container 



(3) Cover 



Select a shallow cup or jar 
(F) that will fit inside the 
frame. Ifnecessary, cut a 
tall jar down to a height of 
3 - 4 cm (I/F2) . 

Select a plastic bag (G) that 
will fit loosely over the 
frame. It may be held in 
place by clipping it with a 
clothespin to a clamp or ring 
that is supported about 10 cm 
above the frame on the ring and 
burette stand (IV/B5) or other 
suitable support. Alternatively, 
a frame to support the bag may 
be constructed out of stiff 
(e.g., coat hanger) wire. 



-236- 



c. Notes 

(i) This frame may be used to support a strip of chromatography paper or 
suitable substitute for either ascending or descending chromatographic operations. 

For ascending operations, the 
solvent container (F) remains 
at the bottom of the frame. The 
Paper strip, with one end just 
touching the solvent, is hung 
from the wire with a paperclip 
The spot or spots of substance 
to be separated is located at 
the lower end of the strip, 
just above the solvent. The 
apparatus should be kept 
covered by the plastic bag (G) 
during the course of the experi- 
ment to keep solvent evaporation 
Spot -11 I ■ to a minimum. 




'Solvent 



(ii) In order to use the frame for descending operations, the solvent container 



(F) is placed on the top shelf (D) 




Solvent 



The paper strip is then hung from the solvent 
container, held in place with a 
paper clip or clothespin, and 
with a short piece folded over 
to dip into the solvent. The 
spot is located near the top of 
the strip, outside the solvent 
container. The solvent front 
then moves down the paper in 
the course of the experiment. 



Spot 



(iii) If a sufficiently large jar is available, it may be used as a cover in place 
of the plastic bag (G) . 



-237- 



B. QUANTITATIVE CHROMATOGRAPHIC EQUIPMENT 



Bl. Liquid-Column Apparatus 



L 






(1.) Col 



umn 



a. Materials Required 
Components 
(1) Column 



q u Items Required 
1 Glass Tube (A) 



Cotton or Glass 
Wool (B) 



1-Hole Stopper (C) 
Glass Tubing (D) 



Dimensions 

Approximately 1 . 5 cm 
outside diameter, 
25 cm long 



To fit tube 

Approximately . 5 cm 
diameter, 5-10 cm long 



Silica Gel (E) 



28-200 mesh 



-238- 



b. Construction 



(1) Column 



(A) 




Fire polish both ends of the 
glass tube (A) to eliminate 
sharp edges. Push a small wad 
of cotton or glass wood (B) 
about 1 cm into one end as a 

plug. 

Insert the small glass tube (D) 
into the stopper (C) and push 
the stopper into the large 
glass tube (A) , and support the 
column in a vertical position 
in a burette clamp (IV/B5) or 
other suitable support. 

To pack the column with the 
stationary medium, make a 
slurry with several grams of 
the silica gel (E) and water. 
Pour this slurry into the top 
of the column, and allow the 
water to drain through the 
small glass tube (D) , while the 
moist silica gel is retained 
by the plug (B) . If necessary, 
pour additional slurry into the 
column until about 15 cm of 
the column is packed with 
silica gel and about 1 cm of 
water remains on top of the 
silica gel. If desired, the 
packing operation may be 
hastened by applying slight 
suction, by means of the 
suction-filter flask (VI/A4) 
coupled with a suction pump, 
aspirator (V/A8) or other source 
of suction. 



-239- 



c. Notes 

(i) The flow of liquid through the column may be controlled, if desired, by the 
addition of a stopcock, or flexible rubber tubing coupled with a pinch clamp 
(IV/A4) or glass bead (III/B1) . A glass nozzle may also be added to the free end 
of the flexible tubing. 

(ii) To use this apparatus, the water remaining on the column is allowed to 
drain until less than 1 cm remains to cover the silica gel. Then a small quantity 
of a solution of colored material to be tested, in a concentrated form, is gently 
pipetted on to the medium. The desired solvent is then added to the column, and 
the column is allowed to drain slowly, using either gravity or very slight suction. 

As the solvent moves down the column, carrying the substance with it, 
separation will occur, as indicated by colored zones appearing on the medium. As 

additional solvent is added to 



■Solvent 




Movementof 

Colored "Zones 



the column, the zones themselves 
will migrate down the column; 
if sufficient solvent is added, 
each zone, consisting of a 
specific component of the sub- 
stance tested, may be washed 
off the column and recovered 
separately. 



(iii) In addition to separating components of a substance and washing them down 
the column with one solvent, it is possible to use additional solvents to wash 
down a component or components that do not migrate at all with the first solvent. 
To do this, allow the column to drain until less than 1 cm of the first solvent 
remains on top of the medium, then add the second solvent to the column and proceed 
with the washing as described above. 

(iv) Other interesting results may be obtained by reversing the order of solvents 
used, in successive runs, with the same test substance. For example, alcohol and 
water are two solvents that may be used, in either order, to separate a mixture 
of vegetable dyes or ink. 

(\| One of the chief advantages of the liquid-column method of chromatographic 



-240- 



separation over paper chromatography is that the components of the substance 
tested are recovered individually for use in further experiments or in quantita- 
tive determinations. For example, a measured quantity of the test substance, in 
a known concentration, is added to the column, and the solvent used and the 
solutions recovered are measured. Then the components eluted are submitted to 
volumetric or gravimetric quantitative analysis to determine the proportion of 
each component present in the original sample. 

(vi) Substances other than 28 - 200 mesh silica gel, and solvents other than 
alcohol or water, may be used in liquid-column chromatography. Further experi- 
mentation, as well as research into the technical literature on chromatography, 
is suggested for the development of this technique. A useful reference for this 
purpose is Erich Heftmann, Chromatography, Second Edition , (New York: Reinhold 
Publishing Corporation, 1967) . 



-241- 



XII. MULTIPURPOSE SYRINGES 

Many chemical techniques and experiments are readily performed using disposable 
plastic syringes. Some of these uses will be described in this section, and the devices 
have been grouped according to the concepts they illustrate. In addition to those 
uses given here, syringes can also be used in column chromatography, ion exchange 
devices, and other areas in chemistry. 

A. TECHNICAL DEVICES 



Two items of use in the chemistry laboratory are included here. 
GAS STUDIES APPARATUS 



Included here are several ways in which syringes may be used in studying the 
production, collection, and properties of gases. 

C. DIFFUSION APPARATUS 



Diffusion of both gases and liquids can easily be studied with the aid of plastic 
syringes . 

D. OXIDATION APPARATUS 



This section describes a number of devices used in the study of oxidation reactions. 
E. ANALYTICAL APPARATUS 



These devices are used in experiments to determine chemical formulae, structures, 
and molecular weight . 

F. CONDUCTANCE APPARATUS 



The variation in conductivity of different solutions can be studied with the aid 
of several devices which are fairly easily constructed with disposable syringes. 



-242- 



A. TECHNICAL DEVICES 



Al . Dropper/Pipette 




( U Syringe 



a. Materials Required 
Components 

(1) Syringes 

b. Construction 
(1) Syringe 



Qu I tems Required 

1 Plastic Disposable 
Syringe (A) 



Dimensions 
Capacity 10-50 ml 



Select a calibrated, plastic 
disposable syringe (A) with a 
volume appropriate for the 
desired use. 

c . Notes 

(i) In the smaller sizes, disposable syringes make excellent droppers with an 
advantage being that the amount dispensed is measurable. Similarly, they can be 
used for the same purposes for which pipettes are used. In the larger sizes, 
syringes can substitute for burettes in titration experiments. Finally, syringes 
may be utilized in calibrating improvised flasks, beakers, etc., of unknown 
capacity. 

(ii) Placing a medium-sized diameter needle (inside diameter approximately 
0.03 cm) on the syringe nozzle will allow solutions to be carefully and accurately 
delivered, drop by drop. 



-243- 



A2 . Pump 




(2) Connecting Tubing 



(1) Syringe 



a. Materials Required 
Components 
(1) Syringe 



(2) Connecting 
Tube 



b. Construction 



(1) Syringe 



(2) Connecting Tubing 



q u Items Required 

1 Plastic Disposable 
Syringe (A) 



Plastic or Rubber 
Tubing (B) 



Dimensions 

Capacity approxi- 
mately 2 ml 

Approximately 10 cm 

long, diameter to 

fit syringe nozzle (A) 



Take a plastic, disposable 
syringe (A) with a volume appro- 
priate for the desired use. 

Attach a length of plastic or 
rubber tubing (B) to the 
syringe nozzle when the pump is 
to be used in hard-to-reach 
places. 



c. Notes 

(i) To use the pump, connect the tubing to the object from which gas or liquid 
is to be removed. Withdraw the plunger to draw gas or liquid into the syringe. 
Then remove the tubing from the object or container, direct the tubing into an 
appropriate container or waste receptacle , and depress the plunger to expell the 
gas or liquid through the tubing. 



-244- 



(ii) With two modifications, 



the syringe may be used to provide continuous pump- 
ing action without removing the 
tubing from the object from 
which substances are pumped. 
Make a small hole in the base of 
the syringe barrel with a drill 
or hot wire, and add a pinch 
clamp (IV/A4) to the tubing to 
close it off. In use, the 
tubing is connected to the 
object from which gas or liguid 
is to be removed. Then the 
pinch clamp is removed from the 
tubing and the hole in the 
syringe barrel is covered with 
a finger. The plunger is withdrawn to draw material into the syringe. To expell 
the contents of the syringe through the hole, the tubing is closed with the pinch 
clamp, the hole is uncovered, and the plunger is depressed. 




Pinch Clamp 



-245- 



GAS STUDIES APPARATUS 



Bl Gas Production and Collection Device * 




" ^ — Bd B 



\ 



(?) Connecting Tubing 



(3) Reaction Chamber 



V 



(1) Syringe 



t) 



a. Materials Reguired 
Components 
(1) Syringe 



(2) Connecting 

Tube 



(3) Reaction 
Chamber 



q u Items Reguired 

Plastic Disposable 
Syringe (A) 

Rubber or Plastic 
Tubing (B) 

Glass Tubing (C) 



Hard Glass Test Tube 
or Flask (D) 

1-Hole Stopper (E) 



Dimensions 



Capacity 10-50 ml 



2 cm long, diameter 
to fit syringe 

nozzle (A) 

Approximately . 5 cm 
diameter, 10 cm long 

Capacity 20-100 ml 

To fit test tube or 
flask (D) 



b. Construction 



(1) Syringe 



(3) Connecting Tubing 



Select a plastic, disposable 
syringe (A) of appropriate 
capacity. 

Connect the short piece of 
flexible rubber or plastic 
tubing (B) to the syringe 
nozzle . 

Heat the glass tubing (C) suffi- 
ciently to bend it to a slight 
angle (about 30°) . Connect 



*Adapted from Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968), p 19. 



-246- 



one end of the glass tubing to 
the rubber or plastic tubing (B) . 

(3) Reaction Chamber Seal a hard glass test tube or 

flask (D) (capacity from 20 to 
100 ml, depending on the desired 
use) with a one-hole stopper (E) . 
Use a rubber stopper if caustic 
materials are to be used in the 
apparatus. Insert the free end 
of the glass tubing into the 
hole in the stopper. 

c. Notes 

(i) This simple reaction apparatus, suitable for either lecture demonstration 
or student laboratory use, may be employed in a number of ways. In the simplest 
qualitative experiments, the use of the syringe allows liquids to be introduced 
into the reaction chamber where they react with solids or other liquids. A 
number of gases can be produced using this or similar devices. For example, 
injecting a 3% solution of hydrogen peroxide from the syringe into a suspension of 
dried yeast and water in the tefetube will yield oxygen gas. Also, injecting a 
concentrated solution of baking soda from the syringe into vinegar will yield 
carbon dioxide. Finally, injecting vinegar into water and a piece of magnesium 
ribbon will cause hydrogen gas to be liberated. The gas liberated will collect in 
the syringe, pushing the plunger out as more and more gas is given off. Turning 
the plunger slightly will assure that the gas is at atmospheric pressure. 

(ii) This apparatus may also be used for quantitative studies in the above 
reactions. The solid reactants must be carefully weighed or measured, and the use 
of the syringe allows very precise amounts of liquids to be introduced into the 
reaction chamber. The volume of the gas evolved may be read from the syringe. The 
change in volume of gas in the syringe may be plotted against time to give a 
measure of the rate of reaction. In addition, the volume of gas liberated may also 
be plotted as a function of temperature and/or the concentration of one or more of 
the reactants used. 

(iii) In a third type of experiment using this apparatus, solids which give off 
gases when heated are placed in the test tube, and the gas is collected in the 
syringe. Begin with the syringe plunger fully depressed, and as the gas is evolved, 
it will push the plunger back, giving a quantitative measure of the amount of gas 
produced. In using this device, clamps to hold both the test tube and syringe are 
needed. As an example, red lead can be heated in the test tube, and the gas 



-247- 



evolved collected in the syringe. It should be noted, however, that this will 
spoil the test tube. Instead, potassium permanganate can be used, and no spoilage 
of the test tube will occur. However, some asbestos wool must be put in the upper 
end of the test tube to prevent pieces of the potassium permanganate from entering 
the syringe. 

(iv) The experiments based on the use of this apparatus are adapted from 
Nuf field O-Level Chemistry, Collected Experiments, (London: Longmans /Penguin 
Books, 1967), pp 9, 229-231, 297-299. 

(v) If a glass reaction chamber is not available or is not desired, a second 

syringe, the same size as the 



<€ 



v- 



Holes 





(- Slit 



€ 






Collecting 
Chamber 



Connecting 
Tubing 




React ] on 

Chamber 



first but slightly modified, 
may be substituted. First, 
with a hand drill or hot nail 
or wire, bore two holes, approx- 
imately 0.3 cm in diameter, 
opposite each other about half- 
way along the length of the 
barrel. With a drill and saw 
or hot nail, make a slit in 
the syringe plunger as shown. 
Push the plunger into the 
syringe, and lock it in place 
by inserting a nail approxi- 
mately 0.3 cm wide and 5 cm 
long through the holes in the 
barrel and slit in the plunger. 
Place in the lower syringe a 
small piece of material which 
will react with the liquid to 
be placed in the upper syringe. 
Replace the plunger in the 
lower syringe, insert the nail 
stop, and depress the plunger 
until the nail prevents further 
movement. Draw a quantity of 
liquid into the upper syringe, 
and fasten the two together 
with the short piece of tubing. 
Next, inject all of the liquid 
into the lower syringe and 



-248- 



leave the upper syringe plunger in the depressed position. As gas is given off in 
the lower syringe, it will expand and push out the plunger of the upper syringe 
until the upper syringe is filled with gas or the reaction stops. Solids and 
liguids which can be used as outlined to produce gases include animal charcoal and 
hydrogen peroxide (to form oxygen), metals and dilute acids, carbonates and acids. 

(vi) The above modification is based on a design by Andrew Farmer, "The 
Disposable Syringe — A Rival to the Test Tube?, " School Science Review, CLXXIV 
(1969), 30-31. 



■249- 



B2 . Micro-Generator 



(1) Syringe 




(2) Beaker 



a. Materials Required 
Components 

(1) Syringe 

(2) Beaker 

b. Construction 

(1) Syringe 



(2) Beaker 



C .Notes 



Qu 

: 



Items Required 

Disposable Plastic 
Syringe (A) 

Glass Jar or Beaker (B) 



Dimensions 
Capacity 10-50 ml 



To accommodate syringe 
as shown 



Select a plastic, disposable 
syringe (A) of a size appro- 
priate to the amount of gas 
desired. 

Select a glass jar or beaker 
(B) such that the syringe can be 
rested in it more or less 
vertically. 



(i) As an example of its use, the micro-generator can be employed to generate 
hydrogen sulphide qas (H2S) . Simply place a small piece of ferrous sulphide in the 
syringe, and put a small amount of dilute hydrochloric acid in the beaker. Draw 
a portion of the acid up into the syringe until it touches the ferrous sulphide, 
and leave the syringe resting in the beaker. The gas will collect in the syringe, 
above the acid. If desired, the needle may be reattached to the syringe when it 
comes time to bubble the gas through a test solution. 



*Adapted from L. A. George, "Two Further Uses for Disposable Syringes," School Science 
Review, CLXX (1968), 113. 



■250- 



B3 . Gas Solubility Device/Reaction Rate Chamber 




(1) Syringe 



(2) Plug 



a. Materials Required 
Components 

(1) Syringe 

(2) Plug 

b . Construction 

(1) Syringe 



(2) Plug 



q u Items Required 

1 Plastic Disposable 

Syringe (A) 



Nail (B) 



Dimensions 

Capacity approxi- 
mately 2 5 ml 

To fit syringe 
nozzle (A) 



Take a plastic, disposable 
syringe (A) of 25 ml or other 
desired capacity. 

Use the nail (B) to completely 
seal the syringe after a 
substance has been drawn into 
it. 

c. Notes 

(i) A number of simple solubility experiments may be done with syringes that 
can be sealed airtight. For example, the syringe may be half filled with cold 
water, with the plunger just above the water level. Seal the nozzle, and when 
the plunger is withdrawn further, air will be seen to bubble out of the water. 
This same demonstration may be repeated with distilled water, or cold water through 
which CO2, O2, N2, etc., have been bubbled. A slightly more sophisticated demon- 
stration involves water through which has been bubbled for about five minutes. 
When a small amount of bromothymol blue is added, the solution will be yellow. 
Add this to a sealed syringe, and as the plunger is withdrawn, CO2 will bubble out 
and the color of the solution will change to pale green. If the syringe is shaken, 



-251- 



the CO2 will be redissolved, and the solution will once again be yellow. The 
experiment may be tried repeatedly. 

(ii) A single syringe can also be used to illustrate the effect of pressure on 
solubility. Attach a short length of rubber tubing to the nozzle, and also attach 
a clamp or piece of wire to the rubber tube which can be used to close the tube. 
Fill the syringe half full of water, and fill the remainder of the barrel with CO2 . 
Shake the syringe vigorously, then hold the tube under water, release the clamp 
(or loosen the wire), and note the rise in water level in the syringe. Repeat the 
experiment, but depress the syringe plunger while shaking it. There will be a 
noticeable difference in the rise of the water level. 

(iii) The above experiments have been adapted from Andrew Farmer, "The Disposable 
Syringe — A Rival to the Test Tube?," School Science Review , CLXXIV (1969), 35-37. 

(iv) Another experiment that can be performed with the sealed syringe involves 
the relationship between reaction rate and pressure. Fill the syringe partially 
with vinegar and add sodium bicarbonate. Carbon dioxide will be given off, and 
this reaction can be speeded up or slowed down and stopped by decreasing or 
increasing the internal pressure with the plunger, respectively. This experiment 
is based on Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968), p 6. 



-252- 



34. Charles' Law: Volume/Temperature Device 



Q£> 




(1) Sy 



ringe 




(2) Weight 



a. Materials Required 
Components 
(1) Syringe 



(2) Weight 

b. Construction 
(1) Syringe 



Qu 

: 




Items Required 

Plastic Disposable 
Syringe (A) 

Small Eyed Screw (B) 
Lead Sinker or Weight (C) 



Dimensions 
Capacity 35 ml 

To seal syringe 
nozzle (B) 

Approximately 30 g 



Make two small holes in the 
bottom of the syringe barrel 
(A) with a hand drill or hot 
wire. 



Holes 



* Adapted from Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968), p 32. 



-253- 



on 




Screw a small, eyed screw (B) 
into the syringe nozzle to seal 
the nozzle and to provide an 
attachment for the weight (C) . 



(2) Weight 




Hang a lead sinker (C) or other 
suitably sized weight (approxi- 
mately 30 g) from the eyed 
screw. 



c. Notes 

(i) With the plunger set so that a 35 cc volume of air is trapped in the 
syringe barrel, the device is put into a container of hot water. Water will be 
seen to enter the syringe barrel as the expanding air leaves it through the small 
holes (the effect will be more visible if a drop of vegetable dye is placed in 
the nozzle depression before beginning) . Varying amounts of water will enter the 
syringe depending upon the water temperature. Good quantitative data can be 
gotten by comparing the water temperature with the amount of water entering the 
syringe (or the air volume of the syringe after the water enters) . The device 
should be removed from the water to return the air volume to its original reading 
for each temperature/pressure reading. 



-254- 



C. DIFFUSION APPARATUS 



CI. Liquid Diffusion Device 



o 



&£> 




T 



Jl) Syringe 



a. Materials Required 
Components 

(1) Syringe 

b. Construction 

(1) Syringe 



C .Notes 



Qu I tems Required 

1 Plastic Disposable 
Syringe (A) 



Dimensions 

Capacity approxi- 
mately 50 ml 



Select a plastic, disposable 
syringe (A) of a large capacity 
(35 - 50 ml, for example) . 



(i) To use this device to study diffusion of liquids, fill the syringe almost 
completely with cold water. Then, draw a small amount of colored solution into it 
and let the 'syringe stand. Diffusion should be complete after two or three days. 
Colored solutions which work well include potassium permanganate and copper 
sulphate. 

(ii) This experiment has been adopted from Andrew Farmer, "The Disposable 
Syringe: Additional Experiment, " School Science Review , CLXXVIII (1970), 60. 



-255- 



C2 . Gas Diffusion Device 



(1) Gas 
Container 




OT 



o 



(2) Connecting 
Tubing 




3) Indicator 

Container 




Q'D 



a. Materials Required 
Components 
(1) Gas Container 



(2) Connecting 
Tubing 



(3) Indicator 
Container 



g u Items Required 

1 Plastic Disposable 
Syringe (A) 

1 Rubber or Plastic 
Tubing (B) 

1 Pinch Clamp (C) 

1 Plastic Disposable 

Syringe (D) 

Indicator Solution (E) 
(Limewater or Litmus 
Solution) 



Dimensions 

Capacity approxi- 
mately 25 ml 

Approximately 15 cm 
long, diameter to 
fit syringe nozzles 

IV/A4 

Capacity approxi- 
mately 25 ml 

Approximately 5 ml 



*Adapted from Andrew Farmer, "The Disposable Syringe — A Rival to the Test Tube?, " 
School Science Review, CLXXIV (1969), 35. 



-256- 



b. Construction 

(1) Gas Container 



(2) Connecting Tubing 



(3) Indicator Container 



Select a plastic, disposable 
syringe (A) of about 25 ml 
capacity. 

Use a length of flexible 
tubing (B) to connect the two 
syringes together. Make a 
pinch clamp (C) or use another 
suitable clamp to close the 
tubing. 

Select a plastic, disposable 
syringe (D) with the same capa- 
city as that used for the gas 
container. Fill it with the 
indicator solution (E) . 



C. Notes 



(i) Place an indicator solution (e.g., limewater) in the indicator container. 
A gas (e.g., CO2 ) is collected in the gas container syringe and the two syringes 
are connected by the tubing. When the clamp is released, the gas will diffuse 
until it reaches the indicator solution and causes a reaction (white precipitate 
when CO2 meets limewater) . The time taken for the gas to diffuse may be measured. 

(ii) A slight modification of the indicator container will allow a comparison 

of gas diffusion rates in air 



Holes , 



<° 



t 

\ 

0.".: 




d 



^- Hole 



and in a partial vacuum. This 
is done by making two holes 
opposite each other near the 
mouth of the syringe barrel 
with a hand drill or heated 
nail. Then one hole is made in 
the plunger, as shown. The 
holes should be made so that a 
nail can be pushed through the 
barrel and plunger. 



-257- 



Gas 



To repeat the above experiment with a partial vacuum, the nail is removed 

from the indicator syringe 
and several ml of indicator 
solution are drawn into the 
syringe. Then the tubing, 
closed by the clamp, is attached 
to the syringe. With the clamp 
in place the plunger is pulled 
back, to create a partial 
vacuum, and the nail is pushed 
through the syringe barrel and 
plunger to hold the plunger 
in position. Gas is collected 
in the other syringe and 
allowed to diffuse to the 
indicator solution, and the 
time taken is compared to the 
results of the first experiment. 




-258 



D. OXIDATION APPARATUS 



Dl. Oxidation Indicator: Membrane Type * 



(2) Membrane 



(1) Syringe 
Assembly 




a. Materials Required 
Components 
(1) Syringe Assembly 



(2) Membrane 



b. Construction 

(1) Syringe Assembly 



<BQ 



I 

Cut 



q u Items Required 

1 Plastic Disposable 

Syringe (A) 

1 Nail (B) 



Thin Sheet Rubber (C) 

Rubber Band or Thin 
Wire (D) 



33 



"TO 



Holes 




r 



Hole 



Dimensions 
Capacity 25-50 ml 

Approximately . 2 cm 
diameter, 4 cm long 

Approximately 
5 c m x 5 c m 



Take a medium to large capacity 
(25 - 50 ml) plastic, disposable 
syringe (A) . Cut off the end 
of the barrel near the nozzle. 
Then, with a hand drill or hot 
nail, make two holes approxi- 
mately 0.3 cm in diameter 
opposite each other near the 
mouth of the barrel. 

In the same fashion, make one 
hole in the stem of the plunger, 
near the plug, as shown. 



*Adapted from Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968), p 6. 



-259- 

Insert the plunger into the 
syringe barrel, and push the 
nail (B) through the holes in 
the barrel and plunger to fix 
the plunger in position. 

(2) Membrane Cut a 5 cm x 5 cm square of 

thin sheet rubber (C) (from a 
toy balloon, for example) . 
Stretch it over the open end of 
the syringe barrel and secure 
it in place with a rubber band 
(D) or length of thin wire. 

C. Notes 

(i) This simple device will give a visual indication that oxidation is taking 
place. For example, if wet steel wool or a piece of cotton soaked in alkaline 
pyrogallol [Note (i) XII/D41 is inserted into the barrel of the syringe and the 
plunger fixed in place with the nail , as the material reacts with the oxygen in 
the air the pressure inside the syringe will gradually be lowered. This can be 
seen since the rubber sheet will be pulled further and further into the syringe. 



-260- 



D2 . Oxidation Indicator: Displacement Type * 




(1) Syringe 



(2) Beaker 



a. Materials Required 
Components 

(l)Syringe 

(2) Beaker 

b. Construction 

(1) Syringe 



(2) Beaker 



Qu Items Required 

1 Plastic Disposable 
Syringe (A) 

1 Jar or Beaker (B) 



Dimensions 

Capacity approximately 

35 ml 

To support syringe 



Select a plastic, disposable 
syringe (A) of medium to large 
capacity (35 - 50 ml) . No 
modifications are necessary. 

Choose a small glass jar (B) , 
beaker, or other container 
that will support the syringe, 
as shown. 



c_ Notes 

(i) Place a portion of wet steel wool (it may have to be washed in vinegar 
to remove the anti-rust coating) in the syringe barrel and position the plunger 



*Adapted from Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968}, p 2. 



-261- 



so that some predetermined air volume is trapped in the syringe. Place the syringe 
into a small amount of water in the beaker so that the nozzle is under water. As 
the steel wool reacts with the oxygen in the air, pressure inside the syringe will 
drop and water will be drawn up into the syringe barrel. Dyeing the water with 
non-fast vegetable dye will make the visual display more evident. 

Cotton wool or other absorbent material soaked with alkaline pyrogallol 
[Note (i) XII/D4] may be substituted for the wet steel wool. 



-262- 



D3 . Oxidation Rate Indicator 




(1) Indicator 



a. Materials Required 
Components 

(1) Indicator 

b. Construction 

(1) Indicator 



C. Notes 



Qu I tems Required 
1 Respirometer 



Dimensions 
BI0L/VIII/D1 (1) 

Construct this item according 
to directions given for the 

Respirometer, biol/viii/di(1) 



(i) Begin operation of this device by fastening the plastic tubing to the 
reservoir and to the nozzles of the syringes. Fill the reservoir with water which 
has been colored with non-fast vegetable dye. Items which react with oxygen in 
the air, including wet steel wool, white phosphorus, or alkaline pyrogallol (soaked 
cotton wool) , are placed in the barrel of one syringe, where they react, removing 
oxygen from the trapped air. This results in a lowering of pressure which causes 
the colored water to be drawn from the reservoir into the clear tubing. The 
second syringe serves as a control, containing only air. The rate of the reaction 
can be judged from the speed with which the water column moves toward the syringe. 



* Adapted from Paul D. Merrick Experiments with Plastic Syringes, (San Leandro, 
California: Educational Science Consultants, 1968), p 11. 



-263- 



D4 . Stoichiometry Device * 



1) Syringe 



(2) Connecting Tubing 




(3) Glass Tube 



(4) Water Container 



a. Materials Required 
Components 

(1) Syringe 

(2) Connecting Tube 



(3) Glass Tube 



Qu 



(4) Water Container 



Items Required 

Plastic Disposable 
Syringe (A) 

Rubber or Plastic 
Tubing (B) 

Glass Tubing (C) 



Glass Tubing (D) 

1-Hole Stopper (E) 
Cotton (Cotton Wool) (F) 

Pan or Tray (G) 



Dimensions 

Capacity 10 ml 
or more 

To fit syringe 

0.5 cm diameter, 
2 cm long 

2-3 cm diameter, 
10 cm long 

To fit large tubing 



Capacity approximately 
1 liter 



*From Paul D. Merrick, Experiments with Plastic Syringes, (San Leandro, California: 
Educational Science Consultants, 1968), p 19. 



-264- 



b. Construction 

(1) Syringe Select as many plastic, 

disposable syringes (A) of 

the same capacity (approximately 

10 ml) as desired. 

(2) Connecting Tubing Connect the short rubber or 

plastic tubing (B) to the 
syringe nozzle. Connect the 
free end of the rubber or 
plastic tube to the short piece 
of glass tubing (cj . 

(3) Glass Tubing Seal one end of a large diameter 

glass tube (D) with a one-hole 
stopper (E) and insert the 
glass tube (C) into the hole 
in the stopper. 

Push a small wad of cotton (F) 
(cotton wool) into position 
near the top of the glass tube, 
below the stopper. 

(4) Water Container For the water container, use a 

pan, tray, jar, or beaker (G) 
into which the desired number 
of syringe assemblies can be 
filled. 

c. Notes 

(i) An alkaline pyrogallol solution must be prepared for use with this apparatus. 
Put 10 g powdered pyrogallol [1, 2, 3 — trihydroxybenzene, Cgf^fOH^] and 2 g 
sodium hydroxide (NaOH) pellets into a small flask or test tube. Add about 30 ml 
HoO. Tightly cap the container and shake it until all the solid dissolves. 
Avoid stirring the container to introduce air, as the alkaline solution will 
rapidly absorb oxygen and become useless for the experiment. 

(ii) For experimentation in stoichiometry, several of these syringe assemblies 
need to be set up. Each should have an identical amount of the pyrogallol 
solution (or other reducing agent) in the syringe. Place all the devices open 



-265- 



end down in the water container. Inject varying amounts of the pyrogallol (for 
example, 0.5, 1, 1.5 . . . 10 ml) into the glass tube where it will be absorbed in 
the cotton. The pyrogallol will then react with the oxygen in the air in the 
tube, and continue to react until either the pyrogallol or oxygen is consumed. 
As oxygen is removed from the air, pressure in the tube will fall, and water 
will be drawn up into it from the trough. The height of the water in the tube 
then becomes a measure of the amount of oxygen consumed, and will be seen to be 
proportional to the amount of pyrogallol used, until the upper limit is reached. 



on 



(iii) If glass tubes are not available, syringe barrels may be substituted. 

A short piece of plastic or 
rubber tubing is used to 
connect the upper syringe 
Upper an d lower syringe barrel, 



Syringe 



which is used in an inverted 
position. 




X 



Lower 
Syringe-- 
Sarrel Only 



-266- 



E. ANALYTICAL APPARATUS 



El. Air Composition Device * 



Q 




(1) Syringe and 
Tubing 





(2) Water 
Container 



a. Materials Required 



Components on 


Items Required 


(i) Syringe a nd 2 
Tubing 


Stoichiometry Device (A) 


(2) Water Container 1 


Pan or Tray (B) 


— 


Limewater (C) 


2 


Modeling Clay (D) 
(Plasticine) 


2 


Candles (E) 



Dimensions 



XII/D4, Components 
(1), (2), and (3) 

Approximately 1 liter 



Small wads 

Approximately . 5 cm 
diameter, 5 cm long 



*From Paul D. Merrick, E xperiments with Plastic Syringes, (San Leandro, California: 
Educational Science Consultants, 1968), p 20. 



-267- 



b. Construction 

(1) Syringe and Tubing 



(2) Water Container 



h 



Prepare two syringe and tubing 
(A) assemblies, as described for 

the Stoichiometry Device 
(XII/D4) . 

Support each candle (E) in a 
small wad of modeling clay (D) , 
about 5 - 10 cm apart on the 
bottom of the pan or tray (B) . 
The clay wad must be smaller 
than the diameter of the glass 
tube used. 



& 



Pour sufficient limewater (C) 

into the pan or tray to cover 

the wad of clay and 1 cm or so 
of the candles. 



c. Notes 



(i) To investigate the proportion of oxygen in the air, an alkaline pyrogallol 
solution, prepared according to instructions inXII/D4, is required. Each syringe 
should contain an equal amount of the pyrogallol solution (5 ml, for example) . 

(ii) When the syringe assemblies, with alkaline pyrogallol solution in each 
syringe, and the candles in the limewater have been prepared, light one candle. 
After a few seconds, place one of the syringe assemblies over each candle. Allow 
them to stand for about five minutes after the burning candle goes out to allow 
the limewater to remove CO2 from the air in its tube. At this time, limewater 
will have risen into the tube to compensate for the lostCC^. Mark this level of 
limewater with a wax pencil or felt-tipped marker. 

Using a syringe pump (see XII/A2), remove air from the other tube until the 
limewater rises to the same level in the second tube as it had in the first. Mark 
this level, also. Now, inject alkaline pyrogallol from the syringes onto the 
cotton wads. This will react with the oxygen in the air, and remove all of it if 
enough pyrogallol is used. The water level in each tube will have risen. The 
amount of rise in the first tube (the one containing the candle) will be compared 
to the amount of rise in the second tube. Also, the change in trapped air volume 
in both tubes should be noticed. By doing this, it will be found from the first 
tube that the burning candle removes only about 25% of the oxygen in the air, while 
the change in volume in the second tube will show that air is about 21% oxygen. 



-26E 



E2 . Gas Reaction Chamber 



u 



(1) Syringe 



«dfesilH 



(4) Clamp 



(2) "T" Tube 



e=o 




„(3) Tubinc 



a. Materials Required 
Components 

(1) Syringe 

(2) "T" Tube 

(3) Tubing 

(4) Clamp 

b. Construction 

(1) Syringe 



(2) "T" Tube 



Qu I tems Required 

2 Plastic Disposable 

Syringe (A) 



: 



Glass "T" Tube 



3 Rubber Tubing (C) 



Pinch Clamp (D) 



Dimensions 
Capacity 50 ml 



Approximately 0.5 
dm diameter 

To fit syringe nozzle, 
approximately 8 cm 
long 

IV/A4 



Select two 50 ml plastic, 
disposable syringes (A) . Secure 
the syringes in a horizontal 
position by appropriate supports. 

Use a glass or metal "T" tube 
(B) with three outlets. If 

available, a three-way valve 
(stopcock) may be substituted 

for the clamps and "T" tube. 



* Adapted from Nuffield O-Level Chemistry . Collected Experimen ts, (London : Longmans/ 
Penguin Books, 1967), p 237. 



-269- 



(3) Tubing 



<cz 



\i 



x> 



(4) Clamp 



Connect the two syringes to 
the "T" tube with two short 
pieces of rubber tubing (C) . 
Use a third piece of tubing (C) 
to connect the apparatus to a 
source of gas. 

Use three pinch clamps (0)or 
other suitable clamps to close 
each section of tubing. 



c. Notes 



(i) To determine the number of gram-molecules of hydrogen chloride that react 
with one gram-molecule of ammonia, set up the apparatus as shown in the main 
illustration. Using the correct combination of open and closed clamps, fill one 
syringe with dry amnonia gas, empty it, and repeat one or two more times to "flush" 
the syringe. Follow the same procedure with the other syringe using dry hydrogen 
chloride. Then, fill the first syringe with 40 cc of the dry ammonia and fill the 
second with 50 cc of the dry hydrogen chloride. With the two syringes open to 
each other but closed to the atmosphere , inject the hydrogen chloride into the 
syringe of ammonia. The two gases will react, forming ammonium chloride. That 
about 10 cc of hydrogen chloride remains unreacted is shown by passing the gas over 
damp indicator paper. Thus, 40 cc of amnonia reacts with 40 cc of hydrogen 
chloride. 



-270- 



F. CONDUCTANCE APPARATUS 



Fl. Conductance Device 



(1) Injecting 
Syri nge 



(2) Receiving 
Syringe 




a. Materials Required 



Components 




Qu 


Items Required 


(1) Injecti 
Syringe 


ng 


1 


Plastic Disposable 
Syringe (A) 


(2) Receivi 
Syringe 


ng 


1 


Plastic Disposable 
Syringe (B) 


(3) Wire 




2 


Insulated Wire (C 


(4) Tubing 




1 


Plastic or Rubber 



Tubing (D) 



Dimensions 

Capacity approxi- 
mately 35 ml 

Capacity approxi- 
mately 35 ml 

Approximately . 3 cm 
diameter, 50 cm long 

To fit syringe 
nozzles, 2 cm long 



b. Construction 

(1) Injecting Syringe 



Use a 35 ml plastic, disposable 
syringe (A) , with no modifica- 
tions, for this component. 



*Adapted from Andrew Farmer, "The Disposable Syringe — A Rival to the Test Tube?, 
School Science Review, CLXXIV (1969) , 32-34, 



-271- 



(2) Receiving Syringe 



C 




v^ 



Hole 



Take a 35 ml plastic, disposable 
syringe (B) and with a hand drill 
or hot wire make two holes, 
approximately 0.2 cm in diameter, 
opposite each other near the 
base of the barrel. 



(3) Wire 




Epoxy Glue 
Seal 



Remove about 1.0 cm of insula- 
tion from each end of both 
wires (C) . Insert one bare end 
of each wire through the holes 
in the syringe barrel (B) . Seal 
the holes with epoxy glue, taking 
care to see that no epoxy covers 
the bare wire inside the syringe 
barrel . 



(4) Tubing 



c .Notes 



Connect the two syringes to- 
gether with a short piece of 
plastic or rubber tubing (D) . 



(i) This apparatus may be used to investigate the variation of conductance as two 

solutions are mixed. The wires 
are connected in series to a 
1.5 volt cell and an ammeter as 
shown. One liquid is placed in 
the receiving syringe, another 
in the injecting syringe, and 
the current is measured on the 
ammeter. Then the solution in 
the injecting syringe is gra- 
attery dually fed into the receiving 

syringe, and any changes in the 
current are noted. Conductance, 
the reciprocal of resistance, 
may be calculated from the 




Ammeter 



-272- 



current and voltage: 



»"f 



mhos 



R 



To Gas Supply 



(ii) Solutions which may be tested in this apparatus include water in the 
receiving syringe and salt solution or HC1 solution in the injecting syringe; 
dilute H2SO4 in the receiving syringe and Ba(0H)2 solution in the injecting syringe; 
and dilute HC1 in the receiving syringe with NaOH in the injecting syringe. 

(iii) This device, with one modification, may also be used to investigate the 

variation of conductance as a 
gas is bubbled into a solution. 
The injecting syringe is removed 
and replaced with a section of 
plastic or rubber tubing that 
connects the remaining syringe 
to a gas source. For example, 
the syringe is filled with a 
limewater solution, and the 
current is noted on the ammeter. 
Then CO2 is passed through the 
limewater, and the change in 
current as well as the change in color of the solution can be seen. Phenolphtha- 
lein can also be added to the limewater initially, and the color change from red 
to clear will indicate the neutralization has occurred. 




Battery 



Ammeter 



-273- 



F2. Constant Volume Conductance Device 



(3) Injecting 

Syri nge 



(2) Extracting 

Syringe 



(4) Wire 




a. Materials Reguired 
Components 

(1) Container 

(2) Extracting 
Syringe 



U Items Reguired 
1 Jar with Lid (A) 



Plastic Disposable 
Syringe (B) 

Rubber or Plastic 
Tubing (C) 



Dimensions 

Capacity approxi- 
mately 200-250 ml 

Capacity approxi- 
mately 20 ml 

Diameter to fit 
syringe nozzle; length, 
about 1 cm shorter 
than jar height 



-274- 



(3) Injecting 
Syringe 

(4) Wire 



b. Construction 
(1) Container 



Plastic Disposable 
Syringe (D) 

Insulated Wire (E) 




Holes for 
Wires 



Holes for 
Syringes 



Capacity approxi- 
mately 20 ml 

Diameter 0.3 cm, 
50 cm long 



Puncture four holes in the jar 
lid (A) . Make the two outside 
holes about 0.5 cm in diameter 
to accommodate the syringe 

(B,D) nozzles. Make the two 
inner holes about 1 - 2 cm apart 
and 0.4 cm in diameter, to 
accommodate the insulated wire 

(E) . 



(2) Extracting Syringe 



(3) Injecting Syringe 



Push the nozzle of a plastic, 
disposable syringe (B) through 
one of the outer holes in the 
jar lid. Attach the rubber or 
plastic tubing (C) to the 
syringe nozzle from the inside 
of the lid. 

Push the nozzle of a second 
plastic, disposable syringe (D) 
through the other outer hole 
in the jar lid. 



-275- 



(4) Wire 



Syringes 



oo/\r>n 




Strip 5 - 7 cm of insulation 
from one end of each wire (E) . 
Push each stripped end of wire 
through the inner holes in the 
jar lid, from the outside of the 
lid. Allow about 8 - 9 cm of 
each wire to extend from the 
inside of the lid. 



c. Notes 

(i) In order to use this apparatus to investigate variations in the conductance 
of a solution as its composition (but not its volume) is changed, the wires from 
the container must be connected, in series, to a 1.5 volt battery and an ammeter. 
[See diagram, Note (i), XII/F1.] A solution, such as water, is placed in the con- 
tainer. A second solution (concentrated salt solution, for example) is placed in 
the injecting syringe and the lid placed on the jar. Current is measured; then a 
measured amount of solution from the injecting syringe is added to the container, 
the solution mixed well, and volume of solution egual to that added to the con- 
tainer is withdrawn with the extracting syringe so that the electrode depth is 
unchanged. Current is again measured, and conductance calculated as described in 
Note (i), XII/F1. 

(ii) This eguipment is adopted from Andrew Farmer, "The Disposable Syringe — 
A Rival to the Test Tube?," School Science Review, CLXXIV (1969), 34-35. 



-276- 



BIBLIOGRAPHY 

A number of texts have proved to be extremely valuable references to the 
Inexpensive Science Teaching Equipment Project, and these are listed below. 

American Peace Corps, Science Teachers' Handbook, 

(Hyderabad, India: American Peace Corps, 1968) . 

This handbook contains many ideas for improvising 
science teaching equipment. 

Association for Science Education, The School Science 

Review, (London: John Murray) . 

A quarterly journal containing articles on 
science experiments and equipment in all the 
sciences at all school levels. 

Association for Science Education, The Science Master's 



Book, Part 2 (Chemistry) Series 1-4, (London: John Murray). 

These materials, selected from The School Science 
Review, describe apparatus and experiments for a 
wide range of chemistry activities. 

Coulson, E. H., A. E. J. Trinder, and Aaron E. Klein, Test 

Tubes and Beakers: Chemistry for Young Experimenters, (Garden 

City, New York: Doubleday and Company, Inc., 1971) . 

This book describes simple apparatus and experiments 
for youngsters in a home laboratory. 

Bowker, M. K., and A. R. D. Hunt, Making Elementary Science 

Apparatus, a Handbook for Teachers in Tropical Areas, (London: 

Thomas Nelson and Sons, Ltd., 1968) . 

This book outlines instructions for construction 
and use of inexpensive, elementary science apparatus. 

The Portland Project Committee, Teacher Guide, Chemistry of 

Living Matter, Energy Capture, and Growth, (Portland, Oregon, U.S.A.: 

The Portland Project Commiittee, 1971) . 

This guide is one of a three-year sequence integrating 
biology, chemistry, and physics into one secondary 
science program. Student guides are also available. 

Richardson, John S., and G. P. Cahoon, Methods and Materials 
for Teaching General and Physical Science, (New York, Toronto, and 
London: McGraw-Hill Book Company, Inc., 1951) . 

This guide describes investigations and laboratory 
techniques for secondary level physics and chemistry. 



-277- 



United Nations Educational, Scientific, and Cultural Organization, 

UNESCO Source Book for Science Teaching , (Paris: UNESCO, 1962). 

This book, recently revised, contains many simple 
ideas for teaching-science at a. relatively 
elementary level. 

In addition to the above texts, the materials from a large number of projects in 
the files of the International Clearinghouse on Science and Mathematics Curricular 
Developments at the University of Maryland have also been particularly valuable. 
Further details of these projects may be found in: 

The Seventh Report of the International Clearinghouse on 
Science and Mathematics Curricular Developments, 1970. (College 
Park, Maryland, U.S.A.: University of Maryland, 1970) . 

This is a source of information on curriculum 
projects throughout the world, and indicates 
materials available, project directors, publishers, 
etc. The Eighth Report will be available in late 
1972. 



-278- 



ALPHABETICAL INDEX 



Air Composition Device 

Alcohol Burner, Modified 

Alcohol Burner, Simple 

Ammeter, Hot Wire 

Ammeters (See Galvanometers) 

Anesthetizing Chamber 

Aperture/Slit Combination 

Aquarium, Breeding 

Aquarium, Jug or Carboy 

Aquarium, Plastic Bag 

Aquarium, Quickly Made Demonstration 

Aspirator 

Aspirator 

Baermann Funnel 
Balance, Compression Spring 
Balance, Current 
Balance, Equal Arm 
Balance, Extending Spring 
Balance, Micro- 
Balance, Pegboard 
Balance, Rubber Band 
Balance, Simple Beam 
Balance, Single Pan 
Balance, Soda Straw 
Balance, Spring 
Balance, Spring Lever 
Ball-and-stick Models 
Basket Sieve 
Bath, Sand 

Bath, Water or Steam 
Battery, Simple 
Beaker 

Beating Sheet 
Beehive Shelf 
Bell Jar 
Berlese Funnel 
Bi-metal Strip 



Page 

CHEM/2 66 
CHEM/40 
CHEM/3 8 
PHYS/255 

BIOL/261 
PHYS/113 
BIOL/147 
BIOL/146 
BIOL/148 
BIOL/145 
BIOL/103 
CHEM/117 

BIOL/114 

PHYS/12 

PHYS/261 

PHYS/24 

PHYS/9 

PHYS/22 

PHYS/17 

PHYS/5 

PHYS/8 

PHYS/32 

PHYS/20 

PHYS/36 

PHYS/2 

CHEM/193 

CHEM/127 

CHEM/18 8 

CHEM/18 9 

PHYS/185 

CHEM/109 

BIOL/101 

CHEM/173 

CHEM/111 

BIOL/117 

CHEM/59 



-279- 



Bird Trap, Potter 
Blowpipe for Charcoal Block 
Bottle, Specific Gravity 
Bottle, Wash 
Bottom Sampler 
Box Trap, Simple 
Bulb Holder with Bulb 
Burette 

Burette and Ring Stand with Attachments 
Burner, Candle 
Burner, Charcoal 
Burner, Fuel System for Gas- 
Burner, Gas 

Burner, Modified Alcohol- 
Burner, Simple Alcohol- 
Butterfly Net 

Cage, Ant Observation 

Cage, Cockroach 

Cage, Cylinder 

Cage, Glass 

Cage, Glass Jar 

Cage, Housefly 

Cage, Jar 

Cage, Wire 

Cage, Wooden Frame 

Candle Burner 

Carbon Dioxide Production Chamber 

Cart, Elementary 

Cart, Heavyweight 

Cart, Lightweight 

Cell, Chemical 

Cells, Dry Cell Holder with 

Centrifuge 

Centrifuge, Hand Drill 

Chamber, Transfer 

Charcoal Burner 

Charles' Law: Volume/Temperature Device 

Chemical Cell 

Chromatographic Device 

Chromatography Apparatus, Liquid-Column 



BIOL/126 

CHEM/191 

CHEM/69 

CHEM/114 

BIOL/82 

BIOL/119 

PHYS/191 

CHEM/61 

CHEM/90 

CHEM/35 

CHEM/36 

CHEM/43 

CHEM/4 9 

CH EM/40 

CHEM/38 

BIOL/94 

BIOL/173 

BIOL/163 

BIOL/167 

BIOL/176 

BIOL/159 

BIOL/165 

BIOL/169 

BIOL/185 

BIOL/180 

CHEM/35 

BIOL/269 

PHYS/61 

PHYS/75 

PHYS/66 

PHYS/177 

PHYS/180 

CHEM/153 

CHEM/149 

BIOL/226 

CHEM/36 

CHEM/252 

PHYS/177 

BIOL/255 

CHEM/237 



-280- 



Chromatography Device, Horizontal Paper 

Chromatography Device, Horizontal Paper 

Chromatography Device, Horizontal Paper 

Chromatography Equipment, Vertical Paper 

Chromatography Equipment, Vertical Paper Strip 

Circuit Board 

Clamp, Wooden Pinch 

Clamp, Wooden Screw 

Cleaner, Test Tube 

Clock, Classroom 

Clock, Water 

Collapsible Heating Stand 

Coil with Cores, Multipurpose 

Composition of Air Device 

Conductance Device 

Conductance Device, Constant Volume 

Condenser 

Cone Sieve 

Cover Slip, Glass Slide and 

Crystalline Packing Models 

Culture Flask 

Current Balance 

Decade Resistor 

Deflagrating "Spoon" 

Demonstration Thermometer 

Dessicator 

Diffraction Holes 

Diffusion Chamber 

Diffusion Device, Gas 

Diffusion Device, Liquid 

Dish, Petri 

Dissecting Needles 

Dissecting Pan 

Distillation Apparatus, Condenser 

Distillation Apparatus, Simple 

Double Bond Structures 

Dredge 

Dropper 

Dropper 

Dropper /Pipette 



CHEM/224 

CHEM/22 6 

CHEM/22 8 

CHEM/230 

CHEM/234 

PHYS/195 

CHEM/78 

CHEM/80 

CHEM/179 

PHYS/52 

PHYS/44 

CHEM/8 8 

PHYS/235 

CHEM/266 

CHEM/270 

CHEM/2 73 

CHEM/138 

CHEM/12 6 

BIOL/30 

CHEM/217 

BIOL/214 

PHYS/261 

PHYS/209 

CHEM/177 

CHEM/57 

CHEM/181 

PHYS/137 

BIOL/258 

CHEM/255 

CHEM/254 

CHEM/113 

BIOL/39 

BIOL/51 

CHEM/138 

CHEM/136 

CHEM/207 

BIOL/60 

BIOL/49 

CHEM/66 

CHEM/242 



-281- 



Dry Cell Holder with Cells 
Dryer, Electric Lamp 
Drying Tower 
Dynamo/Motor 

Elasticity Device 
Electrolysis Apparatus 
Electroplating, Mirrors and 
Enzymatic Reaction Chamber 
Expansion Device, Gas 

Fermentation Tube, Balloon 
Fermentation Tube, Durham 
Fermentation Tube, Syringe 
Filter 

Filter Flask, Suction- 
Flame Test Wire 
Flask Generator (Gas) 
Flask, Light Bulb 
Flask, Suction-Filter 
Flasks, Volumetric 
Forceps 
Forceps 

Fuel System for Burners, Gas 
Funnel, Baermann 
Funnel, Berlese 
Funnel, Glass Bottle 
Funnel, Separatory 

Galvanometer, Elementary Moving Coil 
Galvanometer, Elementary Tangent 
Galvanometer, Moving Coil 
Galvanometer, Repulsion Type 

Galvanometer, Tangent 

Galvanometer with Multipurpose Coils, Moving Coil 

Galvanometer with Shunts, Moving Coil 

Galvanometer with Shunts, Tangent 

Gas Burner 

Gas Burner, Fuel System for 

Gas Collection Device, Plant 

Gas Collection Device, Seedling 

Gas Diffusion Device 



PHYS/180 
CHEM/18 5 
CHEM/18 3 
PHYS/217 

PHYS/102 
CHEM/145 
PHYS/116 
BIOL/263 
PHYS/103 

BIOL/247 

BIOL/248 

BIOL/249 

PHYS/128 

CHEM/12 9 

CHEM/17 6 

CHEM/165 

CHEM/107 

CHEM/129 

CHEM/68 

BIOL/48 

CHEM/72 

CHEM/43 

BIOL/114 

BIOL/117 

CHEM/110 

CHEM/132 

PHYS/266 
PHYS/246 
PHYS/285 
PHYS/249 
PHYS/272 
PHYS/292 
PHYS/296 
PHYS/276 
CHEM/49 
CHEM/43 
BIOL/265 
BIOL/267 
CHEM/255 



-282- 



Gas Expansion Device 

Gas Generator, Flask 

Gas Generator, Kipp's 

Gas Generator, Simple, and Collecting Apparatus 

Gas Production and Collection Device 

Gas Reaction Chamber 

Gas Solubility Device/Reaction Rate Chamber 

Gauze Wire 
Generator, Micro- 
Geometric Structures, Models 
Glass, Measuring 
Glass, Watch 
Glassware, Light Bulb 
Glassware Technigues and Accessories 
Grappling Bar 
Grappling Hook 
Growth Chamber, Plant 

Heating Shelf 

Heating Stand, Collapsible 

Holder, Multi-purpose Design 

Holder, Test Tube 

Hydraulic Press 

Hydrometer 

Incubator, Egg 

Incubator, Microorganism 

Indicator, Displacement Type Oxidation 

Indicator, Membrane Type Oxidation 

Indicator, Oxidation Rate 

Inoculating Needles 

Insect Collector, Night Flying 

Insect Spreading Board 

Interference Strips 

Jar, Bell 

Killing Jars 
Kinetic Theory Model 
Kipp's Generator 
Kymograph 

Lenses and Prisms, Optical 
Lens with Holder 



PHYS/103 

CHEM/165 

CHEM/167 

CHEM/163 

CHEM/245 

CHEM1268 

CHEM/250 

CHEM/82 

CHEM/24 9 

CHEM/215 

CHEM/64 

CHEM/112 

CHEM/109 

CHEM/1 

BIOL/87 

BIOL/85 

BIOL/155 

CHEM/83 
CHEM/8 8 
CHEM/73 
CHEM/7 6 
PHYS/96 
PHYS/108 

BIOL/200 

BIOL/219 

CHEM/2 60 

CHEM/2 5 8 

CHEM/262 

BIOL/218 

BIOL/105 

BIOL/99 

PHYS/138 

CHEM/111 

BIOL/96 
CHEM/220 
CHEM/167 
BIOL/234 

PHYS/121 
PHYS/130 



-283- 



Light Bulb Glassware 

Light Bulb Glassware, Rack for 

Light Bulb Glassware, Stand for 

Light Source 

Liquid-Column Chromatographic Apparatus 

Liquid Diffusion Device 

Magnetic Field Apparatus 

Magnetic Field Apparatus with Multipurpose Coils 

Magnetizing Coil and Magnets 

Magnets 

Magnets, Magnetizing Coil and 

Magnifier, Illuminated Hand 

Magnifier, Water Filled 

Magnifying Glass, Water Bulb 

Manometer 

Masses, Box of 

Membrane-type Oxidation Indicator 

Measuring Glass 

Metal Sheet Shelf 

Microbalance 

Micro-generator 

Microscope, Adjustable 

Microscope, Glass Stage 

Microscope, Hand-Held 

Microscope, Match Box 

Microtome, Hand 

Mirrors and Electroplating 

Model, Kinetic Theory 

Models, Ball-and-stick 

Models, Crystalline Packing 

Model Units, Molecular 

Mortar and Pestle 

Motor/Dynamo 

Motor, Simple 

Moving Coil Galvanometer 

Moving Coil Galvanometer with Multipurpose Coils 

Moving Coil Galvanometer with Shunts 

Multipurpose Coil with Cores 

Multipurpose Design Holder 

Multipurpose Stand 



CHEM/107 
CHEM/100 
CHEM/102 
PHYS/111 
CHEM/237 
CHEM/254 

PHYS/238 

PHYS/241 

PHYS/231 

CHEM/125 

PHYS/231 

BIOL/7 

BIOL/2 

BIOL/3 

BIOL/251 

PHYS/30 

CHEM/258 

CHEM/64 

CHEM/7 4 

PHYS/22 

CHEM/249 

BIOL/24 

BIOL/14 

BIOL/19 

BIOL/21 

BIOL/35 

PHYS/116 

CHEM/22 

CHEM/193 

CHEM/217 

CHEM/198 

CHEM/120 

PHYS/217 

PHYS/212 

PHYS/285 

PHYS/292 

PHYS/296 

PHYS/235 

CHEM/73 

CHEM/98 



-284- 



Needles, Inocul ating 
Net, Butterfly 
Net, Dip 
Net, Lift 
Net, Plankton 

Optical Screen with Holder 
Optical Board and Accessories 
Oxidation Indicator, Displacement Type 
Oxidation Indicator, Membrane Type 
Oxidation Rate Indicator 

Pendulum, Simple 

Pestle, Mortar and 

Petri Dish 

Pipette 

Pipette/Dropper 

Pipette, Transfer 

Plankton Net 

Plant Growth Chamber 

Plant Press (Field Type) 

Plant Press (Laboratory Type) 

Press, Hydraulic 

Prisms and Lenses, Optical 

Pulse 

Pump 

Rack for Light Bulb Glassware 

Rack, Bamboo Test Tube 

Rack, Wooden Test Tube 

Rate Indicator, Oxidation 

Reaction Chamber, Gas 

Reaction Rate Chamber/Gas Solubility Device 

Rectifier, Silicon 

Rectifier (2 Plate) , Sodium Carbonate 

Refraction Model Apparatus 

Relaxing Jar 

Reptile Hook 

Resistor (Carbon) , Variable 

Resistor, Decade 

Resistor (Nichrome) , Variable 

Respirometer 



BIOL/218 

BIOL/94 

BIOL/54 

BIOL/71 

BIOL/65 

PHYS/124 
PHYS/119 
CHEM/260 
CHEM/258 
CHEM/262 

PHYS/50 

CHEM/120 

CHEM/113 

CHEM/67 

CHEM/242 

BIOL/224 

BIOL/65 

BIOL/155 

BIOL/140 

BIOL/142 

PHYS/96 

PHYS/121 

PHYS/49 

CHEM/243 

CHEM/100 

CHEM/103 

CHEM/105 

CHEM/2 62 

CHEM/2 68 

CHEM/250 

PHYS/168 

PHYS/162 

PHYS/126 

BIOL/98 

BIOL/132 

PHYS/202. 

PHYS/209 

PHYS/204 

BIOL/270 



-285- 



Respirometer 

Ring and Burette Stand with Attachments 

Ripple Tank 

Ripple Tank Accessories 

Sand Bath 

Scalpel, Razor 

Scalpel, Strapping 

Scissors 

Screen, Hand 

Screen with Holder 

Screw Clamp, Wooden 

Seine, Two-Man 

Separatory Funnel 

Shelf, Beehive 

Shelf, Heating 

Shelf, Jar Cage 

Shelf, Metal Sheet 

Shunts, Tangent Galvanometer with 

Shunts, Moving Coil. Galvanometer with 

Sieve, Basket 

Sieve, Cone 

Sieve, Soil Organism 

Single Bond Structures 

Slide and Cover Slip, Glass 

Slit, Adjustable Single 

Slit/Aperture Combination 

Slits, Fixed Single and Double 

Slits, Multiple 

Snare 

Soil Organism Sieve 

Source, Light 

Spatula 

Spatula, Test Tube Cleaner or 

Specific Gravity Bottle 

Specific Gravity Device 

"Spoon', Deflagrating 

Spreading Board, Insect 

Spring Balance 

Spring Balance, Compression 

Spring Balance, Extending 



BIOL/273 
CHEM/90 
PHYS/81 
PHYS/90 

CHEM/18 8 

BIOL/43 

BIOL/41 

BIOL/45 

BIOL/56 

PHYS/124 

CHEM/80 

BIOL/68 

CHEM/132 

CHEM/173 

CHEM/83 

BIOL/161 

CHEM/174 

PHYS/276 

PHYS/296 

CHEM/127 

CHEM/12 6 

BIOL/110 

CHEM/203 

BIOL/30 

PHYS/136 

PHYS/113 

PHYS/134 

PHYS/133 

BIOL/130 

BIOL/110 

PHYS/111 

CHEM/178 

CHEM/17 9 

CHEM/69 

PHYS/107 

CHEM/177 

BIOL/99 

PHYS/36 

PHYS/12 

PHYS/9 



-286- 



Stain Bottle 

Staining Vessel 

Stand, Collapsible Heating 

Stand for Light Bulb Glassware 

Stand, Multipurpose 

Stand with Attachments, Ring and Burette 

Steam or Water Bath 

Sterilizer 

Stick Models, Ball-and- 

Still, Water 

Stoichiometry Device 

Strapping Tripod 

Strip, Bi-metal 

Stroboscope 

Structures, Double Bond 

Structures, Geometric 

Structures, Single Bond 

Structures, Triple Bond 

Suction-Filter Flask 

Sun Dial 

Switch 

Tangent Galvanometer 

Tangent Galvanometer, Elementary 

Tangent Galvanometer with Shunts 

Tank, Ripple 

Techniques and Accessories, Glassware 

Temperature/Volume Device: Charles' Law 

Terrarium, Glass 

Terrarium, Simple 

Test Tube Cleaner or Spatula 

Test Tube Holder 

Test Tube Rack, Bamboo 

Test Tube Rack, Wooden 

Test Wire, Flame 

Thermometer, Demonstration 

Thermostat 

Timer, Ticker Tape 

Tower, Drying 

Transformer, Iron Wire Core 

(6 volt output, 120 volt mains) 



BIOL/33 

BIOL/31 

CHEM/8 8 

CHEM/102 

CHEM/98 

CHEM/90 

CHEM/18 9 

BIOL/215 

CHEM/193 

CHEM/141 

CHEM/2 63 

CHEM/8 6 

CHEM/59 

PHYS/93 

CHEM/207 

CHEM/215 

CHEM/203 

CHEM/213 

CHEM/129 

PHYS/41 

PHYS/193 

PHYS/272 

PHYS/246 

PHYS/276 

PHYS/81 

CHEM/1 

CHEM/252 

BIOL/153 

BIOL/151 

CHEM/179 

CHEM/76 

CHEM/103 

CHEM/105 

CHEM/176 

CHEM/57 

BIOL/207 

PHYS/56 

CHEM/183 

PHYS/140 



-287- 



Transformer, Sheet Iron Core 

(12 volt output, 120 volt mains) 

Transformer, Variable Output 
(120 volt mains) 

Trap, Funnel 

Trap, Piling 

Trap, Potter Bird 

Trap, Simple Box 

Trap, Soil Insect 

Triple Bond Structures 

Tripod, Strapping 

Tripod, Tin Can 

Tripod, Wire 

Tweezers 

Units, Molecular Model 

Vacuum Apparatus 

Vasculum 

Vertical Paper Chromatography Eguipment 

Vertical Strip Paper Chromatography Eguipment 

Vivarium 

Voltmeters (See Galvanometers) 

Volume Determinator 

Volume/Temperature Device: Charles' Law 

Volumeter 

Volumetric Flasks 

Wash Bottle 

Watch Glass 

Water Glass 

Water or Steam Bath 

Water Still 

Wing Tip 

Wire Gauze 

Wire Tripod 

Wormery, Box 

Wormery, Jar 



PHYS/147 

PHYS/153 

BIOL/76 

8IOL/73 

BIOL/126 

BIOL/119 

BIOL/112 

CHEM/213 

CHEM/8 6 

CHEM/84 

CHEM/8 7 

CHEM/72 

CHEM/198 

PHYS/99 

BIOL/136 

CHEM/230 

CHEM/234 

BIOL/191 

PHYS/105 
CHEM/252 
BIOL/244 
CHEM/68 

CHEM/141 

CHEM/112 

BIOL/90 

CHEM/18 9 

CHEM/141 

CHEM/54 

CHEM/82 

CHEM/87 

BIOL/171 

BIOL/168